You are right this is about the home interface but to me that is one of the bigger disruptions. I will see what else we can switch off.

Seriously? Thank you for letting me know; I was going to get an Evo on the 4th but not after learning this. I'm glad I didn't find this out after purchasing.

you should try out sense, many people consider it an improvement over stock android.

I have, and I hate it. Here is a good article I share the same thoughts with: http://news.ycombinator.com/item?id=1330600

I'm surprised nobody in the hacking community has figured out a way to completely replace the HTC Sense/Motoblur/Samsung TouchWiz UI to the default Android UI.

They have - there are ROMs to do that, I've used them on my Hero. They're not very popular though as most people prefer Sense to stock Android.

When you applied these ROMs, can you easily upgrade to any Android version?

Any version to which there's a ROM avaiable, yes. There's a 2.2 Froyo ROM coming out in the next couple of weeks that's been demonstrated on YouTube.