I think that making a high resolution game is a step in the right direction for Dave. His other games are great of course, but I think that he lost lots of potential players with the "retro" look.
I think he also gained players because of the "retro" look.
The pixel art in his latest games is beautiful.
It's going to be difficult to match that with budget 3D.
The screenshots in the article don't look that great.
They are serviceable, but have a cartoon look in some places and not others.
There is also an anti-aliasing problem. I know it drives some people crazy to see "the jaggies" running around the edges of a character or building. Maybe it can be fixed and won't be a problem in the final game.
I suppose Dave Gilbert has a certain style of gameplay in mind that he thinks would work better with a 3D engine. It's probably not a point-and-click adventure style though. The article didn't mention the control scheme.