I have heard that 4.0 will also support multitasking. As long as it's a setting that can be turned on and off I'm all for it. Personally I won't use it unless I'm working on a document and want to listen to music at the same time.
Flash support would be nice, but not a dealbreaker for me at all. I totally understand and even somewhat agree why Apple is anti-Flash, but until everyone switches to HTML 5 it is a needed evil for many people.