I've been using TANE's Content Manager from the early days of TANE and I don't like having to go back to TS12's CM which I am required to do on a regular basis. The ability to have multiple windows is, perhaps, it's greatest advantage.
But there could be improvements as in any software. Since it is a simple Windows window I see no reason why we can't re-colour, change fonts and use most of the "standard" windows features. Perhaps there is an issue maintaining some similarity between Windows and Mac.
I sometimes have two version of TANE running. I can tailor the splash window so I know which one I am looking at but it is impossible to tailor the CM windows. The ability to colour backgrounds, borders, etc would help.
I don't use the thumbnail view of CM. Frankly you can't see enough to make it worthwhile for my purposes. I didn't even know it existed until someone complained the other day that it wasn't working. i took one look and decided it wasn't for me.
Re Ish's comments: I use TANE's CM in conjunction with AssetX and TANE's Preview Asset for CC purposes. Works for me!
I've seen the possible replacement for CCP and it looks promising. But I never used CCP because it was too slow and I doubt if I will use it's replacement. But I will happily test it for N3V.
I think content creators have very different requirements for CM and associated programs so I am sympathetic to Ish's views of a tailored/cut down CM.