Consider the other side of the coin. Consider that you like to role play out a situation, you have a decent relevant social skill, and all it boils down to is a dice roll. How does the encourage creative play? How does that encourage the players to think as their characters? How is a die roll more fun?
1) I did mention that I give bonuses (or in rare cases, penalties) for description, because I do like description.
2) One could argue that this is like complaining that you could know a lot about combat as a player, have a decent Base Attack Bonus as a character, and then still miss by rolling poorly. Yep, the game does allow for that. I kind of like the fact that it does. Succeeding all the time would be somewhat dull. But I see you've addressed this below.
3) Sounds fun to me. I've had hilarious moments with some of my more personally charismatic players who, after having their average-Charisma PC make a very well-reasoned statement, roll the dice, utterly blow the check, and say, "Okay, that's what I wanted to say, but what actually came out was, 'Oh, don't be such a nazi, you pinhead. Pull your head out.' Just like I've had hilarious moments with the fencers who, upon watching their decently skilled fighters blow an attack, come up with a hilarious method through which their guy skewers the wall instead.
3.5) According to the D&D rules, your character is, at some point in his or her career, going to blow an important attack, misspeak with some important NPC, overlook a hidden object of great importance, and fail to get that critical spell cast by losing your concentration at just the wrong time. It's going to happen. Attacking that idea with "It all comes down to a die roll, so roleplaying doesn't matter" seems wrong to me, because it implies that roleplaying is something that by its very nature leads to success. Roleplaying doesn't let you decide what the weather is like. Roleplaying lets you decide how your character reacts to the weather. (In my opinion, which is only an opinion, and possibly only mine.)
And on that note. I've gamed with martial artists, fencers, boxers and wrestlers. You had better bet that if someone knows this stuff, they make a far more effective fighter, no matter the rules sets. They usually think of creative things to do that are still outside the rules. As a GM you can harsh on them, or you can be thrilled that you've fostered cretivity, interest, and fun in the game.
Interesting. I've had creative ideas come from people with all levels of skill. I'm almost always interested in giving people chances to do fun things (my usual rule is "Some kind of related skill check, usually DC15, for a +2 or +4 to hit" -- so sliding across the table to kick the gun from someone's hands is a Balance check, while swinging from a chandelier is a Climb check), but I don't see what the player's level of ability has to do with it. I'm a fifth-degree black belt, and if I'm playing a first-level Smart Hero with no combat feats and a strength of 10, I wouldn't expect to get any mileage out of "Okay, my PC doesn't know anything about combat, but he'd like to step back as he's punched and see if he can catch the other guy's arm, and then punch the other guy hard, aiming for the throat, so that even someone with my low strength can do a lot of damage." That's a blatant attempt to get an unfair advantage because of my personal abilities.
By the same token, I don't let wizards with no ranks in Disable Device use Mage Hand to "randomly move the tumblers of a lock" in hopes of having it work, because wizards with no ranks in Disable Device don't know what tumblers are. It's an attempt to game the system, and I don't consider that a good thing. (Note that I consider this different from letting a wizard/rogue or wizard with cross-class Disable Device ranks use Mage Hand to try and pick a lock -- in this case, the character has the appropriate knowledge and skill ranks, and is just trying to use his character's existing skills in a slightly different way. I'd probably bend the rules to let the Wizard/Rogue pick the lock using Mage Hand, using either Disable Device at a -4 penalty or a Concentration check, whichever is lower. It's not as good as doing it up close and personal, but it's a lot better than nothing.)
I'm honestly not sure whether we agree or disagree, because I'm not sure at what level you're arguing. If you're saying "A wizard/rogue should be able to try to pick a lock with Mage Hand," then I agree with you, although the level at which we'd penalize such an attempt will likely vary. But if you're saying "A wizard with no ranks in Disable Device should be able to twiddle the tumblers with Mage Hand", then I think you're allowing your players to use their personal knowledge, knowledge that their PCs wouldn't have, to their PCs' advantage. And I disagree with that. Doesn't mean your game is bad or wrong or evil. I just don't advocate doing it that way.
Flexible combat is great. Fun ideas are great. But a fun idea shouldn't let a character with no ranks in Balance, Climb, or Jump do a standing leap over a balcony to catch a chandelier, swing across the room, land on a greased silver platter, and skateboard on it across the room and under the closing portcullis (although I wouldn't outright forbid it -- I'd just require the appropriate skill checks and then nod sympathetically when the character inevitably failed). That's not me slamming creativity. That's a player attempting to violate his own character concept for personal advantage -- the antithesis of roleplaying.