"The shield, the limitation of only two weapons, superior grenade usage, and slower movement are mechanical reasons. However, when you get down to it, Halo is MUCH more situational than just about any other FPS. When you play UT, you spend the match running around jumping while collecting as many weapons as possible and trying to own everything on the field. In Halo, you have to consider that many situations combined with your weapons loadout will yield very different results from all sides. Knowing how to quickly take down a shield and kill them is important and knowing how to do it faster than anyone else will give you plenty of kills. You CAN take damage because of the shield, so when played effectively, you can remain undamaged for quite sometime. In UT, when you hit someone with a couple rockets...you know that the only way for them to recover is to find health kits. In Halo, if you can not finish the job quickly, their shield will recover itself and your attack will have been for naught."
Halo's not even the first to mix a shield and limited weapon loadout to begin with. Also, you're severely overcomplicating it in a way that it "seems" like depth. None of those factors change gameplay from the standpoint you're looking at it. (pseudo-related tangent: I could just engage an enemy in KOTOR and let it hack away, but that doesn't mean that the game is simplistic).
"There really are no one hit kills, special combos, and level based tactical situations to worry about in UT."
Tell that to anyone who has ever ate a flak shell, 2 rockets head on, head shot, shock combo, or a fully charged bio-rifle blob.
"Virtually everything has a counter attack that you must keep in mind.""
"counter-attack?" Please elaborate, because it sounds like buzzword-PR BS.
"The fact is, you can not simply move around a level in the same fashion as UT. At any moment death could come and you should always equip specific weapons depending on what type of area you might be in."
Uh...death can't come at any moment in a UT deathmatch? Now you're just being ridiculous. An instant kill can happen at any time, and I can't count the number of times I've seen someone/myself been frustrated because of kill-after-kill with absolutely no warning or hint.
"Perhaps later on, when I have time, I can explain with more detail just how important those things really are. I also used to feel that Halo had a very shallow multiplayer mode, but upon really learning it with others I discovered just how much MORE there is to it. You don't just run around, aim, and shoot...and if you do, you WILL die."
I'd really like to hear this.
"That's why my comment was NOT an insult. If someone believes that Halo has LESS depth than Doom, that is solid proof that they have not really put in the time with Halo (much less understand how the game can really play)."
His comment was (hopefully) hyperbole.
"LOL.. what a flawed over-generalization. The strategies in Halo are top notch. Everything from situational gun effectiveness to grenade usage."
How is "situational gun effectiveness" different from ANY other FPS? Hell, I'd say UT has better "situational gun effectiveness" than Halo for the simple fact that the primary/secondary fires of many weapons make them useful in more than one situation, but not all. Also, in tight halls, many weapons can have a negative effect (flak/bio-rifle), where Halo only has the grenade and the rocket launcher that are similar to this.