No need to fear posting lots of suggestions. When we do updates to ArtRage we tend to go through the suggestions forum as well as our big-whiteboard-o-ideas ( tm =) ) so the more the merrier as far as I'm concerned!
I think the idea of simplicity and ease of use is something that makes ArtRage what it is, so you're right, it'd be a shame to throw that away.
Regarding wet on wet, I've been doing a watercolour course just recently, and I'd tend to agree, there's very definitely a different feel to it, as well as a wide range of effects possible when working like that it seems. Thanks for the suggestion!