I have looked at UT3, as there is an awesome mod for it called "Angels Fall First:Planetstorm", that I am simply dying to try out (on the ground, in space, actually boarding an enemy capital ship and fighting inside it combat *drools*).
The main problem I really have with Stalker is the what I gather of the rating- M for blood and gore. I am really not into blood and gore (but sadly many people today want to see the grotesque and sickening elements of warfare in the games they play. Both disgusting and pitiable). I am not saying that some blood/gore is bad, but the over-the-top nature of some games with the intensity of violence done to an enemy player is just disgusting and sickening (not physically for me).
Probably the best point I can think of- my dad was watching TV one day, and saw the CoD:MW2 commercial. He remarked that he and several friends of his had talked about it and had said that one could get PTSD (post traumatic stress disorder) from playing MW2, as it is so real looking (he is a US Marine who has done 2 tours in Iraq. So yes, he would know). Of course, the fact that MW2 also sucks for PC (and that I am not going to go and buy a '360 or PS3 to play it) also deters me from buying MW2.
UT3 and Stalker I could probably put up with as- UT3 has a variety of extremely interesting mods for it, and Stalker looks EXTREMELY interesting to me.
And now I must say something that many might disagree with- EA got it right (to a point) with the Battlefield series. Well, MOST of the series. Bad Company&BC2 I can make no comment on, having never played them. But the others I can rather soundly say are engaging, entertaining, fun games. For those unfamiliar with the Battlefield series, the premise of the game is this- capturing "control points". Generally, whichever team controls the highest # of CPs will win as the other teams "tickets", which are a pool of collective "lives" for that team, will "bleed" away. Tickets can also be depleted by killing enemy soldiers.
BF2142 also introduced the "Titan" gamemode, which places the "Titan" a massive aerial fortress that must be destroyed by the opposing team for said team to win (both teams have a Titan). This game mode has no tickets, but the core idea is the same- control missile silos to bombard an enemy Titan's shields, then either hold most/all silos to pound the Titan into proverbial scrap metal, or board the enemy Titan, destroying it from within, or even both.
One of the other things I can think of that keeps an FPS game going is what has helped keep Sins going for many players- the modding community. The Battlefield 1942 community stayed afloat FOREVER (technically speaking, as it is now rather nonexistant), thanks to modders and mods. The same thing happened with BF:Vietnam (probably my favorite Battlefield title). Battlefield 2 has been kept afloat mostly because EA rather botched things up with 2142 (though 2142 is still an excellent title, except for evil DRM for the most part), and because of the HUGE modding community around BF2. One would think modders would move to a newer game correct? In the case of BF2, there are probably 2-3 times as many mods as for BF2142.
Granted, I don't think that "point&shoot everything" gameplay is BAD necessarily (as that is effectively all Nexuiz, my favorite open-source FPS, is), as sometimes I do get the want to just kill/destroy everything in my path. But more often, when I want to blow stuff up, I want to play a game that has at least SOME tactical considerations that I can take into account.