I know that program stability, features and quality are all very much more important but I really think having a consitent gui design for all Cubase’s included plugins would make it feel a but more like 1 complete package.
At the moment you’ve got the pre-Cubase 4 plugins like Overdrive, Step Filter and Tonic.
Then you’ve got all the Cubase 4 style plugins like Chorus, the Delay plugins, Compressor, Limiter, and loads more.
The you’ve got a few newer (Cubase 5 I think) plugins that looks similar but a bit different like the Pitch Correct & Loopmash.
And now you’ve good some new ones in Cubase 7 like the Tube Compressor and Vintage Compress.
My Thoughts are that it should be a relatively simple process to reskin all these plugins with new consistent skins, sure it’s probably not a priority but I think it would be nice to have a more consistent feel.