1. WotC has recently decided to go PDF, and it's got a lot of people excited. They're changing, albeit slowly.
I think they're saddled with a repressed legal team, but it's nice to know they're trying to get into the modern era.
2. From what I hear, for 4th Edition Wizards decided to borrow some aspects of MMO games, and people started complaining that the entire RPG will be like that. And the comparisons of Tieflings to Draenei. What could've been legitimate complaints degenerated into tactless insults.
Honestly, the only thing that's 'really' MMO is the terminology, which they co-opted back to their own words, Defender, Leader (HEALER, PEOPLE, HEALER), Controller and Striker. All basic food groups that D&D has always had, just a little more codified. If anything, the game feels more like Atlus styled JRPG/Strategy game, like Disgaea.
3. Trying to please everyone is impossible, especially given that the expectations and playstyles of the fans want different things. AD&D players want a more minimalist, "rulings not rules" game and don't care as much about game balance, 3rd and 4th players prefer a tight, cohesive ruleset and want class balance (3rd because they're very aware of how unbalanced things get in their Edition). This is just one example, and a generalization of recurring themes I see instead of "all X players are Y."
Yes, but the goal is to be able to get every D&D player to share, as it is right now, each version of D&D is an island, with older folks bemoaning their system is dead.
4. Many players have different ideas. Some people (like some of the 4E guys) say to nerf full spellcasters, others say they should empower the non-fullcasters. Some say both. Others, such as some AD&D players, recommend bringing back restrictions from the Old School games, like no Concentration check to retain spells (if you're damaged, you lose the spell), or making certain spells disadvantageous to use liberally (crafting magic items drains 1 Constitution, haste ages you, etc.) Different players want different solutions, and many see their solution as best.
Well, yes, but on the forums (which is but one aspect of the issue) it's more or less been decided that Magic IS a problem.
5. Well, expecting the GM to fix minor problems when they arise is reasonable. Expecting him to fix gaping flaws in a system is another thing; so many people have tried to fix 3rd Edition, and nothing short of a major overhaul of the system can adequately solve things. There's also the fact that more than a few players like spellcasters being superior in every way, and complain when people try to balance things.
And that's just it, the Pro guys expect GMs to fix the system. In fact, this particular argument has been around since the late 2e, early 3.0 days, at the very least.
6. Well, depends upon the Edition and how overpowered the Wizard is. A spellcaster who's effortlessly cleaning up encounters and making everyone else feel useless is not good sportsmanship, even if it's rules legal. This is especially the case in 3rd Edition. On the other hand, certain classes are so underpowered that they can't really keep up without excessive optimization. An ideal solution is to discuss with the group what their preferred "power level" is: not power in terms of level, but in terms of optimzation, min-maxing, etc.
The issue is the legacy problem. A lot of Players (even those that may not like it) don't want it changed because they don't know how it'll turn out. Or that it's DIFFERENT. Which is what 4e's real problem is. It's NOT like the previous editions, so a lot of players simply turned their nose at it and began making up BS about it as excuses to not try it. Then Paizo comes in and guts the player base, by doing the exact same thing 3.5 did to 3.0, and fans they are proclaims the 'true successors' to D&D, instead of screaming bloody murder for invalidating the previous books (which with every new book of their own, they are doing, but that's how you stay in business...)
In the end, all of us who play D&D, play D&D. And WoTC's goal is to get everyone to play nice with each other and hopefully make some money doing so. Instead, sometimes, it seems to me that people LOVE these battle lines that are drawn and simply want to snipe at each other for not being part of their particular Game Tribe.