Quote Originally Posted by Xelbair View Post
1) Limiting the amount of actions that player can undertake simplifies design of the level(no 3-weapon combos or n-weapon combos)
2) simplified controls - mind you that most games need to be available on consoles - and players need to have fast access to each weapon.. and cycling through inventory midfight destroys immersion, which is a BAD thing.
3) direct ability to control which weapons will be available on stage without forcefully removing them from player(no one likes it when someone takes away their toys) - they can easily limit you to lets say 3 weapons from pool of 12 by providing ammo for quite some time for just those select weapons and/or making enemies drop just those weapons -> this leads to #1 - simpler and more precise design.
4) 'realism' effect - as someone said in here you wouldn't be able to run with whole inventory of heavy weaponry on you.

also by limiting player to few weapons lets them pick weapons that suit their play style, while giving them as many slots as there are weapons forces them to utilize everything(and some players might hate that), plus there will be always a weapon that would feel useless in such case - and by removing ability to compare all weapons at the same time(doable only by hardcore maniacs tbh) you trick players into not noticing it.
The points here are about how it makes it easier to design such games (except for #4 which is the only valid reason for certain types of game). Also, the control thing isn't that big of a deal. Even earlier FPS games had quick switching to alternate between two specific weapons. It shouldn't be that hard to come up with a seamless interface to speed up the access of weapons without having to restrict the player to just two. Again, it is fine for designers to do things that make their job easier but they shouldn't be dressing it as something that is fundamentally better, because it doesn't actually improve the player experience and in many ways limits it.