It's just a matter of taste (no debate)
I like the colors and rounded shapes. The Nimbus LaF theme I'm using is enough for me.
I've also managed to bring back the colorful icons from version 6.
So I'm happy with how it looks.
A new 3D engine might also sound scary. It could be both good and bad.
If it uses JavaFX instead of Java3D (which is very likely), most plugins will have to be rewritten. I don’t think that would be too much of a problem.
If it refers to a rendering engine other than SunFlow and YafaRay, that could be interesting IF they’re open source.