I think general opinion when this has been discussed before is that people don't want it. It would get in the way of media apps.
I would phrase it differently. Full Notification Bar messaging/popup support is a good idea only provided that:
- It is configurable and disabled by default.
- It may have no side effects or otherwise negative impacts when disabled.
Getting in the way should be avoidable and be the default setting.
As one of the design concepts was optimal compatibility with existing APP's made for smartphones it would be a differentiator for Himedia products.
Many competing products following the Android TV (=Leanback) approach will come very soon.