If you don't like the game... play another *shrug* -- why bother with one you don't enjoy. LANs are always the most fun Sharpei Diem, and if that's the only way you like FPS then get together with your friends and do that.
As for the similarities... you said the magic word "sequel". I expected the similarity, but hey, that's just me. I think they are counting on things like adrenaline and new game types / variations (bomb run and double domination) to provide new elements. Along with the changed speed of the game and the weapon changes of course.
Actually IMO the lightning gun forces you to be a good sniper. A good sniper should move after each shot / kill and should have his routes planned in advance. It takes the semi-permanent camping out of sniping and should make snipers more unpredictable. I suspect it will also take more weapon skill to be a good sniper with this weapon (slower firing and IMO less accurate). I think the small size / short line of site in these demo maps make sniping less viable -- it will be interesting to see how it works out on a larger map.
"Spamming" can be a tactic. Some noob blazing wildly is just spamming, but some player keeping you from sniping him with suppresive fire is tactically smart. It allows some cheap kills, but luck is still no match for skill and it's not like you don't respawn and get to take your revenge... repeatedly
It also allows you to shoot your way out of an ambush and creates some very intense fire fights.
I have never been wedded to one style of play. As a result I have enjoyed a wide variety of shooters, from Doom on (although Quake was my first online experience). Take the game for what it is and enjoy it -- or don't play it. Or h*ll, mod it and come up with your own perfect game. The retail release of UT2k3 certainly seems to have all the tools and material needed, well except for time. I don't know about you, but real life never seems to leave me enough of that...