Why are FPS designers so scared of reusing environments?

I've been playing Gears of War lately, and I've been getting a lot out of it. My mate isn't getting quite so much out of it, because he's feeling the sting of ÃƒÂ¢Ã¢â‚¬Å¡Ã‚Â¬75, it's his copy, and he finished the game in 4 days. The other day, a few of us had a debate about whether that was acceptable game design, me being the only one on the Gears side. I felt the labour justified the cost, while the popular view was that the cost didn't match up to the short experience.

I can hear some of you screaming it already: multiplayer. Much and all as I explained the importance of online play in fps design, and how much a motivation that is for the average gamer, the story taking up less than a tenth of the average owners total playing time on such a game, nobody else thought this was reasonable, we're not a Live house.

A friend disgusted me by making the most seemingly irrelevant and actually best point of the game, by referring to GTA, SA in particular. He argued that people could never finish it and still enjoy every minute, and that Epic had no excuse for not being able to do the same. I argued that Epic had created huge set-pieces as part of an on-going narrative in new environments, while Rockstar had created mountains of drag-and-drop errands on routes criss-crossing the same landscapes, and realised I'd painted myself into a corner. Because while GTA didn't stop being fun during any of that, Gears of War just stopped, and all too soon (with a fairly unexciting, generic, boss-battle at that).

So why are shooters so seldom seen to reinvent the same territory? I couldn't get tired of the dodging and butchering in Gears of War, and even if I might, the game ended before I got a chance to. Why not loop the story back through the obstacle course of the games design a few times and mix it up a bit? Would people feel cheated by that? Maybe. Is the attention span of shooter enthusiasts to blame?

In real combat situations, things usually take a bit longer, and assaults often involve more than 20 or 30 enemies. Territory is held onto rather than ran through like a headless chicken with a machine-gun. Why is it that so many shooters instill the palyer with this "you have to get out of here" mentality, where environments are to be ran through rather than explored, are tight schedules really that exciting?

The reality of the situation is, and here I refer again to multiplayer, that players are happy to re-enter the same environment hundreds of times once they know a unique situation awaits them. What sensible reason is there for not applying this knowledge, to the design of more games? My guess is that it's the whole sad thing of trying to be like films again. Well, lads I'm sorry, but the best shooter in the world equates to do a dodgy b-movie as far as narrative is concerned, just let it go. Just give me spawn points for AI and ammo, doors that don't close behind me, all the time in the world and a big gun. It could be the ultimate patch for so many shooters. We could call it de-narratisation, and start some sort of design revolution. Mounting tension is all well and good, but I can read thanks, and when I finish a book I won't read it again for a long time. When I shoot somwthing, I want to shoot something else, soon afterwards.

What do you all think, could shooters handle intense re-use of their environments in a modal, GTA style, mission form, or would it break them?

I dont like them re using envirnonments either, the HAVOc engine is used by nearly every frigging company (all next gen).

They need to create some new ones or next gen games wont go to there full potential.