This is a rant; it is mostly aimed at 4E, but it is just as validly aimed at other games as well that have overly involved combat subsystems.
Most games I've been involved in are generally about relaxing, getting together with friends and having fun. Relaxing is an important part; I play these games to get away from the stress of my day-to-day life, kick back and pretend I'm someone else, doing something I could never hope to do in my own life, facing dangers and obstacles I could never survive in real life. Sure, I like dramatic (and big) battles, but I like to be able to both soak in what is going on, as well as have the time to properly plan my own actions (I have the personal flaw of being a poor tactician and often taking a minute or two to "catch on" to many things).
If I'm engaged in a relaxed game, why must I resort to using tricks to "speed up my combat"? I'm talking about the type of tricks mentioned in several threads about speeding up 4E's combat - halving monster hit points, having PCs roll attack and damage together in the same roll and all the other "tricks" people have presented just to get their combat down to a reasonable time span. Why can't the game just present a combat system in which you can resolve the situation in a reasonable amount of time in the first place. Why do you have to kludge the system to make it work for you? Why is it acceptable?
I think any RPG that requires you to rush through combat by using various tricks or techniques is a telling failure in that part of the game. A combat can be dramatic and exciting without having to be rushed. I don't want to be hastened through running a combat just so I can get it to be over with in a half-hour to hour instead of two-hour, three-hour or longer combats in an RPG. If I can't play through a combat at about the same pace I run the rest of the game and reliably have 15 minute to half-hour combats (or about the same length it takes a group of characters to interact with an NPC or search a non-empty room in the game), I think that's bad game design - a faulty focus placed on one aspect of the game over another portion of the game.