I use Corel Painter since version 9.5 and although there are many flaws and issues, I always come back to it. But there are two huge wishes for future versions I have:
1) Please add finally clipping masks than I can skip the buggy step to mask everything in a layer and add my watercolor brush splatters that than "bleed" through the masking edges. This bug adds hours and hours of extra working time to delete all of these overstepping watercolor white fringes:
2) Transparency issues: When I save my watercolor layers as JPEG or PNG they loose their transparency and have those awful white edges -argh!! And although efforts were made to finally make brushes that are transparent and act like Photoshop's brush engine they are not usable since they do maintain their original color. Instead they make those terrible color shifts. In the end I turned this feature off, since it was unusable.
3) PLEASE: Add a Pencil brush that is that effortless and natural like the Pencil brush in Apple's old version of Notes. The tilted shading is a dream and also the normal lines. It looks so realistic and beautiful. Also the adding color to brush strokes by layering them looks and feels very natural. Here are several examples for that:
4) Add tabs instead of windows for opened files please! Look at this fail - I cannot even read which file is which:
re -white bleeding out - I'd pick up a copy of artrage 5 (free demo available), it has a white (or any other) color remover feature -and play with that.
good luck getting any of those suggestions implemented, as much as corel hates deep legacy code revisions, they do happen once in a blue moon.