I find most of Wayne Reynolds'
humanoids horrendous, but his other stuff is generally acceptable to me.
A bunch of pictures I would
really like to see replaced would be the one for the Displacer Beast (probably the only picture I dislike by Sam Wood), and the ones for most of the Good Dragons, specifically those that have butterfly wings (I believe they are the Brass, Copper and Gold dragons).
The Bronze Dragon was painted so beautifully, why change the style for the others?
Anyway, the topic of art in D&D is a tricky one, mainly because the greatest
strength of D&D art is that it is varied. If there was only Todd Lockwood everywhere, people would get bored very fast.
For a perfect example, ask people about the magmin picture, and you will receive answers that will cover the whole spectrum, from "Glorious" to "Stinky".