Hey so great work so far and frankly 5 stars for sticking with it to make the game better! Seriously, the game is great fun for me and I'm going to get copies for my brothers so we can play together and I thought that I might try and contribute to this game I enjoy and you have spent the time and effort to stick with and make better.
1: Deathwing champion's Halberd of Caliban, It looks pretty cool and you could make it more of a twist by making it less good at defending, but really good at attacking by letting it hit multiple enemies in an arc in front of the terminator and maybe giving it a buff against enemy leaders. Could give it to assault class. Just remember to give it the blue-flame mace piece at the pointy end.
You can see in the one picture where he tried to make it glow how you did properly with the mace of redemption in the game but essentially a two handed mace of redemption with an axe part and two spear parts.
2: Multi-melta or lascannon type weapon? Not sure how I feel about this one but it would be a new different kind of weapon that could be a beam that performs like a concentrated, long-range, continuous damage over time weapon that has great armor penetration. Could then chalk it up to being a weapon the Dark Angels are hiding from the times of the Great Crusade. Really this is one of those excuses you can use again and again since they were out fighting the great crusade before any other space marines existed. They also have private access to certain forge worlds special stuffs.
1: Cyclone Missile Launcher, this one could go as either a weapon or an ability, but if it was an ability it could do more damage and have an appropriate cool down which seems right for a weapon like that. If it was an ability, you could even make it so that there were different kinds of missiles. You could make it so the missiles spiral down hallways so that they have a good spread and splash even in the narrow areas and have a decent area in the more open parts of the space hulk. --If you were looking for equipment that could be cross class or found in level with limited ammunition but gives a significant power boost, this would be a good way to go too since both hands of the terminator are still left open. Apparently says somewhere that the standard one can't be used in space hulks, but you could just make a smaller version (like 2x2 missiles on each shoulder instead of 3x2) and call it something like a tornado Missile Launcher or the Pious Cleansing Launcher (actually, you probably could come up with a better name in like 10 sec's) and give it the background of being one of the closely guarded weapons that the Deathwing have had hidden away since the Great Crusade.
2: Perfidious Relic of the Unforgiven, this one is also pretty flexible as you could make it so that there are different kinds that provide different buffs and so could be cross-class equipment, a team item that gets voted on or chosen prior to deployment in a level, or something you find in level that gives you a boost. If you find it in level you could make it something that has a time limit if you wanted. You could also make it's location randomly generated and give points for finding. If you wanted you could make a Watcher in the Dark follow the terminator squad around with it too if you wanted to get fancy. Otherwise it could just be mounted on the terminator's back or something. I think this one is good because of all the options you have and you could even give some of those options to the host of the server if you wanted. Plus everybody would think it was cool to see the watchers in the dark who can't be interacted with normally anyway.
1: Appearance of the Assault class, honestly not important by any means but if there was something to mess with appearance wise in what is an absolutely stunning game, it would be how boring looking the Assault class kinda feels. Never go to anyone with a problem that you don't have a possible solution for is what I'm told and honestly I thought of the solution before I thought of it as a problem. Dress the assault class up like a Deathwing knight, they are some of the best looking models in the table-top game and as far as adjusting the model goes, you could just put a robe and hood over the existing model and it would look glorious! You did such an absolutely stunning job on the Interrogator-Chaplain that I pray that GW makes a model based on it someday. Robes are kind of one of the selling points for Dark Angels table-top wise and so since you made it so that the assault class equips Deathwing Knight attire, you should just throw a robe on him to make him look the part. Also, makes them more distinct and allows you to show off how good you are at making flashy bits.
You can see awesome pics of robes here and in some of the pics there is a Watcher in the Dark with the Perfidious Relic of the Unforgiven. I also went back and looked at the Assault class armor to make sure I wasn't just being a jack wagon and ignoring the work you put in while just giving my own preferences and saw that some of the ornaments were unique and detailed, and it might be a shame to just cover them up. I still stand by the idea of putting a robe on the Assault class to denote the Deathwing Knight part and to give it more flair as an individual class instead of looking so similar to the heavy, and apothecary classes without their special standout ornaments. I noticed the tactical class has a small robe but it doesn't quite stand out the way the Deathwing Knights one does and looks closer to something you might see in a different chapter, which is fine, but allows for the robe and hood I'm talking about to feel pretty distinctive all the same.
Thanks for the hard work! Keep it up!