I would like to see tooltips in other places. I'd like to see items with similar models without having to click on a tab, for example. I'd like to see screenshots in tooltips. Et cetera.
You could implement useful semantics for shift-hover, ctrl-hover, et cetera.
You could also show scaling ubiquitously in a simple if not entirely accurate way, e.g. "scales at 80% of spellpower." It would be nice to know where scaling occurs in old content.