The highs were always smooth... I don't expect them to change into something sharp. They weren't designed for that anyways (sharpness can lead to fatigue, Aurisonics avoids fatigue; they are musicians' monitors after all).
Regarding how mid-forward things are... I actually feel the UE 900s have a bit of a bass focus on them (they measure that way too, as measured by: Rin, Tyll, and even myself), a slight one, but its definitely there. Which is why I don't see these mid-forward at all.
I'm well aware, doesn't mean I can't wish for some sharpness when songs would benefit from it ;)
I didn't listen to enough of the UE900s to make that call.
Again, me seeing these as midforward might be cause of me having many V and U shaped headphones in the past. So they might only seem midforward to me. But when I listen to a lot of vocal music, including Jazz and some vocal driven parlor-esque music, I really hear how forward the mids are. Really when I listen to most other music I don't hear it as much. But with groups like the midiaeval baebes, it is pretty apparent (to me at least). But I may just not know what true midforward sounds like. I've heard neutral (which these are not) and mid-recessed (which these are definitely not). So by those two comparisons these are mid forward. If only just.