Why won't I switch? Well my final decision hasn't been made yet as I've signed up for a friends playtest when the rules come out. But for now its looking like my interest in 4E is minimal at best. I could go into specifics, but many of the reasons have already been mentioned. So here are a few generalities.
-To start with I haven't seen any really innovative or exciting rules that I feel will improve my game either on its own or without an accompanying negative to a feature of D&D that I currently enjoy.
-I've seen a number of new rules that appear very arbitrary and more designed for the sake of change than for any real improvement in our gaming experience.
-I've been very disappointed with how WotC has managed their customers expectations, and their overall level of support, responsiveness and service to the D&D community. Especially those who raise anything but a totally positive voice to what they have seen so far.
-I'm also upset with many of the dramatic changes that have been made to the magazines, the Realms and other elements of "D&D" that were not directly linked to the system itself. I see the iconic magazines turned into an atrociously managed (to date) collection of generally poor pdf articles ... I see another iconic element of D&D, Forgotten Realms, be hacked apart and then various pieces thrown away while others are tied together with thread from a really bad storyline... and I see honest efforts to communicate (even civilly at times

) be ignored so often that it almost appears to be part of a business plan.
Even though I have a large collection of 3E books, the money is not an issue for me. Gaming is my major vice and I usually like to buy a couple of new books each month. Whether its new settings or new systems I like to read about them and play them. But only the ones that can attract my imagination.
Unfortunately 4E doesn't just have to attract my imagination and sense of wonder, but WotC has to make me disregard all the negatives they have created. Its not that I hold a grudge against 4E. Its just that in todays market, with so many good settings, good systems and companies actually communicating & interested in making my gaming experience more enjoyable, WotC & 4E aren't setting the standard anymore. IMO, they are being measured against the competition, and in many places found lacking.
I hope I didn't ramble too much.