So I've put some hours into MR and would like to give some feedback on my experience so far. I enjoyed the original Spintires (although not nearly as much as some people on this forum), so much of my feedback is based on my experience with the original game.
So, first off I want to say that I really want to see this game succeed. Unfortunately, while MR does improve some things over ST like the graphics and some of the physics, the game still feels very rough and unfinished, and not at all like a 1.0 product. There's also been a lot of regressions and cut content, and some pretty nasty new gamebreaking bugs. Kind of disappointing honestly since this re-release was the same price as the original game (and actually more expensive for me since I got a better sale on ST and bought MR based on how much I enjoyed ST in spite of all its many issues).
My first bit of feedback would be to continue fixing the game-breaking bugs. The first patch is a step in the right direction, although it is really discouraging that multiplayer was broken at launch. That doesn't leave a good first impression at all. Additionally, I lost all progress on the Seashore map when I alt-tabbed out and will have to start over due to the game crashing and corrupting the save (and then steam cloud syncing the corrupt save).
Next, restore the cut content. Especially the missing addons and tires. The E-7310 utility addon with the crane was one of my favorite attachments, and I'm really disappointed that it's no longer in the game. The beacons and cabin protection for the trucks were neat as well and I would like to see them added back to the game. Some of the reworked content is also pretty bad. I really don't like the new garage trailer at all and the B-130 desperately needs diff-lock and chained wheels back to be at all useable.
The new features also need to be fixed and finished properly. I like the concept of the cockpit view, but the current implementation is pretty bad. The side view mirrors need to work, especially if you have a challenge specifically based around using the view. Not to mention how tacky and unfinished the current cockpit UI is right now. Cockpit view also desperately need a keyboard binding (not just a controller button) instead of clicking on the truck. Many times while trying to do other things I end up accidentally clicking on that annoying cockpit camera thing hovering over the cab. Please remove this and just give us a simple keybinding.
On the topic of new features, I have a few thoughts on the progression system. I like that we're encouraged to actually complete the maps now instead of just messing around, but at the same time it feels too restrictive. Maybe instead of awarding all the progression points only upon completely finishing a map, they could be awarded for each task on a map. For example, unlocking a garage would provide a progression point, revealing the full map would also give a point, and each completed objective would also give a point. Additionally, maybe have a system where unlocking a garage lets you spawn a truck of your choice there (with some limits). Maybe if you don't use all the stars at the start, each unlocked garage gives you another star and if you save your stars up, you can get a bigger truck than normal once all the garages have been unlocked. I'm not sure how to balance it, but maybe there could even be some limits on attachments on a per-map basis so an entire truck class doesn't have to be nerfed and have a very useful attachment completely cut just because it's OP on one map.
Randomized truck spawns are a neat idea, but they need some limits on the randomness. Some maps really need the 8x8 trucks, so there should be some guarantee that at least one will spawn somewhere on the map. Maybe maps can have global rules on what trucks will always spawn somewhere on the map, which trucks will sometimes spawn, and which trucks will never spawn. Additionally, each spawn point can have its own list of which of the trucks for the map can potentially spawn at that point and a range of damage/fuel levels for the trucks. Maybe even have the option for a spawn point to not spawn a truck at all so you could have a map with lots and lots of spawn points, but in a given playthrough only a portion of them will have trucks so you have to explore a lot more.
There's also some features I would really like to see added. Maps on the Steam workshop is a really big one. It's one of the things that IMO saved ST. There's honestly not much content in the game as it stands right now, but making it easy for players to use community maps will add immensely to the replay value. More first-party maps would be great as well, especially if we could get some winter-themed maps.
More load variety would also be nice to see as well. I've seen mods with ore trailers and containers, and I've thought it would make for some really interesting map design. That way you don't have to worry about the placement of each log station with respect to each objective, since you could have one place to get logs with an interesting path to the logs objective, but at the same time also have an ore objective that could be right next to the log station, but since you need to get ore, the ore station could be placed somewhere interesting with respect to the ore objective.
In terms of game polish and balance, there's a few major things from ST that ST Plus was able to fix that haven't been addressed in MR. The camera is still really rough. Even just adding the ability to zoom out more would help immensely, although I would also like to see more options to move the camera more freely to "walk around" the truck and survey the terrain.
The fallen trees also need to not be immovable objects. They should be things that could be used as winch points for the UAZ, but the large trucks should be able to drag them without noticing or lift them with the crane. Same thing goes with the small stumps, the large trucks should be able to pull them out with the winch.
The winch also needs a lot of love. Having to click on that little X to release it is really, really annoying. Having a keybinding for this like ST Plus did would be very useful. There's also the little thing of the winch cable not having a texture. That just looks tacky and unprofessional. I wouldn't mind a longer winch either and once that works when the engine is off (at least for trucks where it makes sense like the UAZ), but that's more of a game balance issue than polish.
Overall, MR, like ST before it, has a ton of potential to be an amazing offroad game. It's still (mostly) fun to play right now as long as I don't run into any game-breaking bugs, although I'm kind of taking a break from it at the moment after losing several hours of progress due to that crash and waiting to see how things go with future patches. Hopefully this game will get the love and attention it needs to really shine.
Edit:
I've gone back and finished all the maps on casual. One other thought that came to mind is the lack of balance with the different log loads. Right now, small logs are almost always the way to go (unless you have the E-7310). A single load of medium logs is significantly more difficult to move than using the same truck with two loads of small logs (log carriage and log trailer), yet is worth less load points. As far as long logs go, there's so few trucks that even have an option for a long logs trailer anymore that they're generally not even an option. They're also more difficult to move than two loads of small logs and not worth any more points, so unless you're trying to get the achievement they're not worth the hassle either.
I think ST did this better with having small logs be worth 2 points. Many times I actually used ST Plus to increase the objective points to 12, so I could either do two loads of long logs, three loads of medium logs (or double short logs) or six loads of short logs. Additionally, the weight of medium/long logs need to be proportional to their point value. If short logs are worth two points, then medium logs need to be exactly twice the weight. If they're worth three points, then medium logs should only be 33% heavier. Same idea goes for long logs.
Another thought is the map layouts themselves. This isn't really a new thing, but other than the Deluge/Flood map, the rest of the maps don't feel like a realistic part of a larger world. From a challenge standpoint they're fine and generally provide a nice choice of paths between the logs and the objectives, but otherwise they don't really make any sense.
The roads, garages and fuel depots many times seem to be placed more or less randomly with lots of roads to nowhere and roads not connected to anything else. Maps with tarmac have a loop that doesn't actually connect to the outside world. In short, they don't feel like real-world maps at all.
Thankfully Deluge/Flood is the exception. I really like that map design (for the most part, it doesn't have as much variety as the other maps) since it actually makes sense in the context of a larger world. All of the roads have a purpose and make logical sense in the context of the world. The garage and fuel depot are in logical locations. If we get more first-party maps, I would like to see them follow those design ideas rather than what we have for the other maps.