Remember that Insurgency:Sandstorm is going to be using the UE4 and it not another Source game. With that said, the closest idea on what type of Tickrate we might end up getting is something similar to Rising Storm 2: Vietnam Server configuration.
The game I'm showing you from above is currently running on UE3. The tickrate can only be configured if you modify the 'NetServerMaxTickRate=20' for the .ini extension file. Can't remember excactly where to modify it in the directory file. The best bet for getting a consistent gameplay experience would be something like 60 hz. Be careful when going more than 60 tickrate because it can increase the CPU usage and the memory usage.
Can't say for sure how many Maxplayer are going to be on a server for Sandstorm? I seen a couple 60 tickrates server when I play RS2 on a 64 playerbase. If your were expecting a 60 tickrate server for something like 100 players. Good luck with that, because it going to be very taxing on the hardware and it won't work at all. That why most UE4 multiplayer game, like Playerunkowen Battlegrounds uses 17 Tickrate on server side while Frontline uses 18 Tickrate. Frontline easily has the best netcode than PUBS. I would recommend looking up 'Battle(non)sense' Youtube Channel for more information.
Tl;dr a straight port of insurgency to ue4 shouldn't struggle to run at 60hz on the server if that's what the devs want to target.
Ue4 by default has an unlimited tick-rate only limited by performance/network performance/developer choice (which some of you probably already know). If Sandstorm keeps the same kind of scale as their other games I (anecdotally) can't see any engine based reason for 60hz to be difficult to achieve (source: I'm a dev, and have done most of the network replication programming on my own ue4 game.) If there was one factor that could affect tick rates on a server side it would be ballistics, depending on how authority is handled and what kind of rewind they use but it's only when dealing with fornite scale playercounts where getting adequate tick rates becomes extremely challenging.
Even epic working with their own engine have only achieved 20 hz in fortnite (source) but that's on a way more hectic level of complexity than what I'd expect from insurgency, considering they have to network all of the building/destruction systems as well as everything else. So I mean it's feasible that if the scope of Sandstorm is expanded far beyond the last game it could be more difficult to get a 60 tick rate but in my opinion it's unlikely.
Squad might be a closer example of tick rates, might be worth checking that out.
Good thinking. Had a quick look online and squad as of july last year drops to 25-40 at around 80 players, but they're constantly improving that game so wouldn't expect those to be final numbers
Source (last comment): http://forums.joinsquad.com/topic/27789-higher-server-tickrate/
I end up wondering what the tick rate they set to in Sandstorm because the problem I got for Insurgney(2014) and Day of Infamy is that when you shoot an enemy player/bot in the head, there may be time where the game/server might not be consistent on whenever or not I ended up getting the headshot. Jugging from most NWI server I played on, most server are running on a 64 tick server. There a couple guide out there on reddit where you can configure your server in order in order to get the best experience, especially for competitive play.
It too early to say how many player there going to be and what the estimated tick rate for Sandstorm. We'll see about that.