1) killing the print editions of dungeon and dragon
A tough choice, but a great many people find the current versions of them to be the best the magazines have been in ages - with not just decent content, but content that is just as
usable in a game as in any printed book.
2) lots of thinly veiled insults at previous editions, fans of previous editions, and certain playstyles in the hype leading up to 4E
Yeah, I don't think these were ever truly the 'insults' some felt they were...
3) hyping a product that will never be (virtual table top)
They definitely screwed up there. And have since come out with some decent products, and adopted a policy of not announcing new products until they are definitely on track for completion.
Could definitely be better, sure.
5) laying off D&D employees every six months even though 4E is supposedly doing great
You know, just like they did through the life of 3rd Edition. I'm not a fan of the corporate culture behind such turnover, but I don't think it is reasonable to consider it a bad business decision or a sign of the company doing poorly. They regularly release employees and bring in new ones when they need to amp up production - that's how the company works. I don't like it, but it also doesn't fit in this list.
6) designing the newest edition around an excruciatingly slow combat system that makes playing the game almost unfeasible
Yeah, this just isn't true. Combats have the potential to go long, but they also avoid a lot of the pitsteps that slowed down combats in the last edition. And they have continued to demonstrate a willingness to try and provide options to fix what issues some people have.
7) stopping legal sales of all pdfs
I again disagree with their decision to do so, but don't think it was malicious, nor do I think we have the data to judge whether it was a terrible business decision or not.
8) an astonishing amount of errata and rules updates that invalidates physical books very quickly and is nearly impossible to keep up with
1-2% of a book received errata doesn't "invalidate" the book. An update every other month, posted freely on their website and incorporated into the character builder, is not "nearly impossible to keep up with."
Some don't like the errata - I think it is fantastic, and many agree that WotC being willing to work to keep the game balanced is a genuinely
good decision for the company to make.