After a week of gameplay I can think of this as the biggest problem:
Dificulty curve.
Seriously guys, the dificulty curve can be MURDER on this game. I know that you tried to balance the game by making it more difficult, but you only managed to make it more frustrating. Especially to new people. And this will only leave you with people that are really old at this and start accumulating strength, creating a vicious circle. And this difficulty curve can be broken down into the following:
Equipment. Really, it's RIDICULOUSLY HARD to obtain equipment, if you're not lucky enough to have someone help you. That wouldn't be a problem, but you see, it's also RIDICULOUSLY EASY to lose your hard earned stuff. you spend a few hours "farming" in the wastelands, you get some OK stuff, and you get savagely beaten by a gecko or you receive a stupid critical from a robber. To make matters worse, there's always a chance for you to encounter a PKer. Speaking of which...
PK. PK is rampant, it seems. I understand the thing with PvP everywhere, but in the name of all that's holy, you guys have to realize, there are people that get a kick out of being assholes. The moment they start camping near an entrance just so they can kill anyone coming in to town you have to realize something's wrong. I'm not talking about removing the PvP everywhere thing. But you need to insert some dire consequences for PK-ing in towns (or in SOME towns at least, so they can be considered safe havens). Dunno, some tough guards that pile up on whoever shoots or throws a punch, or something. I have encountered this problem and I'm sure a lot of others have. I swear, i didn't kill a single player since I started playing this, but I've been killed more than a dozen times by other characters (all of them were russian).
Also, you need to set up a bounty system. I seen it's been mentioned above. Put some cash on somebody's head, make use of the terminals or something. However, I'm not talking about NPC's hunting the guy with the bounty. I'm talking about other players being able to hunt the guy. Once they kill him, the money is automatically transferred to the killer's account. It would also be nice if more people can pool money at any time to raise the bounty. A high level guy with some nice and shiny equipment will think twice about pissing other people off when he knows he can get 40 - 50 k in bounty on his head, and other high level players on his back.
Random encounters. Srsly. Travel is slow as fucking hell. I have been told previously that it was even slower. But it doesn't change the fact that it still is slow. To make matters worse, random encounters are too damn scarce. I wandered the wastes FOR A FUCKING HOUR to level up and I got about 12 or 11 encounters. You need to make some special area where you can kill stuff according to the level. This would help more people level up faster. You can create incentives for high level players during the course of the game, just make getting started a little easier.
Speaking of random encounters, they're not quite that balanced. On one hand you get easy encounters, like mantis, or dogs or spore plants. On the other you get RELATIVELY easy encounters, like geckos, robbers and brahmin. The latter are the most likely to get you killed, especially if you're unarmoured. I'm having trouble putting a brahmin down, and I'm level 3, specialised on unarmed and with high agility. Also, robbers can always nail you a critical, sending you back to the replication vats. Paradoxally, robbers are the most likely to land you some ok equipment in the early stages of the game. But if you just started you have absolutely no chance of taking them down unless you're highly specialised in unarmed combat.
And this imposes a development path on you. The game is unplayable for diplomatic or thief characters. If you decide to start with ranged, hell, even melee weapons, you'll have enourmous trouble until you get some decent weapons. And the catch 22 is that you can't get decent weapons most of the time. And even if you do, you can lose them at any time. And that a great game does not make.
I would say that quests are mostly unaccessible to English players, but that's an old problem.
Anyway, that was it. Looking forward to my second week of gameplay.
[edit]
How much longer will the test take?
Also, I don't speak russian (I can barely read Kyrillic), but I can help you with spellchecking and corrections during these holidays if you wish.