The short list of things that people frequently suggest that are either planned or rejected.

32 Bit support:
This will not happen, 32 bit accounts for less than 8% of the Steam user base, and maintaining a 3rd platform that is being superseded just doesn't make sense. Instead of requesting this or donating for us to support it, put that money towards a new 64-bit capable computer (though a lot of systems sold after 2005 are 64 bit capable, you just need to switch to a 64 bit OS).

Linux support:
This is relatively often suggested, it's kind of planned but won't come anytime soon, this is due to the frequency of patches from SCS that makes this infeasible to maintain multiple versions of the mod.

OS X support:
See Linux support

Add mod *:
Generally, we don't add 3rd party mods except for aesthetic ones, this is because map mods bring a whole lot of different issues that we necessarily can't handle. Mods that affect the truck are also generally not accepted since they can have unexpected consequences similar to what we see with save file editing (parts in locations where SCS didn't intend causing crashes, etc.).   The major blocker is the distribution of mods, the larger the mod, the harder it is to distribute. P2p would be an "easy" way, though it still requires infrastructure, in distributing the winter mod, we recently had support from 10gbps.io, even then we pinned a 10Gb port for hours on end, imagine that we'd need that kind of beef every time we updated the mod. Even if we'd get the tail to come quicker, the initial seed is necessary. Add to that, you have to provide a backup since many networks disallow p2p traffic.   We could put the mod behind a paywall, but this is something we rather not, we believe that this mod should be freely available to anyone, with the only requirement being a purchase of either ETS2 or ATS.

More slots on the server:
This is something many people complain about, and we hear ya, we want it too, there's an issue we've not yet been able to nail down. We will increase the limit the moment we can.

VTC panel:
We're planning to make something like that, but there are other things that need to be in place first, this also ties a bit into that what we want to achieve is quite beyond what is feasible with the rate SCS makes patches for the game.

Change speed limiter to */Turn off speed limiter:
Variations of this have been suggested countless times. If you don't want speed limiter, there's EU#2, for everyone else, there are all the other servers, no we won't change the speed limiter on these, it's set to 110 as a compromise.

Add server in region *:
Give us a reason why, show us that there is a community that will use it, if you can't, then no.

Make all servers into one big one:
Maybe, but for the time being, unlikely, latency around the globe vary a lot and makes this incredibly difficult to do without causing more issues.

Private servers:
No, the intent of the mod is MMO, if people get to set up their own servers, the player base will likely be spread out thinner and the map will be even more empty.

Add company skins:
If we were to add every VTC's skin, the download would be quite big, it would also have to be maintained over a long period of time and would add complexities to the testing process.   Allow all players to use the police car: No.