"What do you guys think, not considering the amount of work for a moment?"
I'm not sure I fully understand you, did you really miss the help icons? If you're on 1.7 they should always appear, on 1.8 you must activate them in Admin Features.
The mouseover idea is interesting in a unilingual context but...there are still millions of languages I don't know any way to ask Smarty if the string was translated and I sincerely don't think there are, so I say we currently can't do that.
About the main idea, the RFC you missed is at HelpSystemFutureConcept.
Thanks for your implication.