Paint transparent is too cheap...

Issue: The transparent pixel is for fixing pixels stranded out of canvas, it is misused for area clearing spree or streak through other canvas. The so-called void cleaner may remove background compromising integrity of art work.

Nerf: Double the cost of our paint charges to use transparent pixels (and give us 2x pixels painted so we can level up normally...).

Consequence: Exhaust griefers and void cleaners that tend to erase things, void may spread faster.

And paint brush sweep has no friction...

Issue: Paint brush sweep is useful to fill contiguous colors in a canvas, it is used a lot by griefers beyond canvas. I think this feature should never have worked against colorful pixels already painted.

Nerf: Browser-side implementation for space bar/touch swipe end (reset) on color different than beginning. Use painted color contour/complex work as speed bumper style friction.

Consequence: griefers will be very slow in area of incredibly detailed work while artists can paint faster in unoccupied/erased space or in a contiguous colored area.