And did you see power armors behind every corner in Fallout?
No, they were limited to 2 organizations (which players shouldn't be able to normally join IMHO, but that's different story).
The fact is, that Fonline is not very similar to original Fallouts. Of course, locations, special .. But Modoc in Fallout was peacefull city, in Fonline it is faction battleground.., in Fallout there were only (2 or 3) factions using miniguns, in Fonline everyone use them. So If you want to limit it, be consistent.
Why don't you just add power/advenced power armors to the game? They should be as rare as gauss pistols are - not so rare at all. So much more entertaiment. On battlefields u can see everyone wearing CAs or Metals, thats lame...
Gauss are not so rare.. people who knows can farm them, but i agree that gauss pistol is one example of perfect economy balance of weapons. If you want them, you need to spend a LOT of time to have enought to use regulary gauss build.
PA/APA is not advantage in a combat. From my combat experience, a player in PA or APA is a first dead player. He is target for everyone, and PA and APA animations have more pixels then any other armor siluete => easier to target him. It was same with CA in first session, when CA was not craftable. Lets hunt CA.
But real problem with negative impact on gameplay and population on server, is that there is not any other challenge in the game. No new PVE, no dungeons, no new weapons, no new armors (maybe except CA mkII). Every single item you want you were able to collect until first month, maybe less.
So on one side, adding PA in game could bring back more players who want to get one, on second side, PA in Fonline will be too unfaloutish, as Jovanka B said.