This is a pure example of pigeon chess people. A player who turns into a pigeon, shits all over the table and struts around thinking he's won. Erm, isn't free-for-all action essentially what Quake III: Arena is, and that's deathmatch, or were you referring to team modes or professional duel matches instead? Yes you have missed the point if you're signalling out one cool weapon in UT, every single one has two firing modes which can often be combined, not to mention with strafing and double-dodging, hence where the gameplay depth comes in.
And your final statement about you having more arena-FPS knowledge is laughable using this thread as a reference. All you've done is come in and mentioned the stripped down graphics of Q3 in the pro scene and the spectator mode, you couldn't even bothered to provide evidence or make comparisons between the two movement systems in either games, why you think UT is shallow or any other point for that matter. But oh no, I don't have enough knowledge to understand your mighty kind, this leads nowhere!
OK I'll bite.
Regarding movement you're talking about UT having strafing, ie moving sideways. Like all FPS ever since wolf3d. How is that even remarquable? Meanwhile Q3 has circle jumping, which means that going forward and strafing in a direction while simultaneously turning in the same direction, you will jump further. The rotation needs to be pretty accurate in both amplitude and speed. A famous exemple of it is the raw jump from bridge to rail in q3dm6. Ofc you can even do it backwards if you fancy :
...
Then Q3 movement has momentum through strafe-jumping where, again, precise angles are needed, here's a 2h30 theory vid :
Oh and with cpma you get good old bunnyhopping! In all cases it can be combined with weapons used as movement tools! Because weapons have actual knockback!!!
See? Amazing!!
And you can use it in real games! And ofc weapon knockback can be used to mess with your opponent's movement...
And all these options can be used to attack a position from unorthodox angles, but the weapon based movement options (e.g. rocket jumps) will take a toll on your health which make it risky, especially if the opponent has a lg or rg.
And then there is map control, item timing and delaying, item drops, powerups management or denying, cessing, ...
And I've barely scratched the surface.
Now do entertain me little pigeon and tell me about UT's depth.