I really do like this idea. Or at least the goal you are trying to accomplish. Sometimes I just like to wait to see if anyone else will jump in to discuss first before I reply.
One of the ideas I've had for a while is to have a set of filters that could help with a weekly review. The ability to filter for all projects that do not have a current next action is one of the filters I was thinking would be helpful.
Your idea to somehow highlight these projects is another good way to accomplish this goal. I worry a bit about creating too mush visual clutter, so it would need to be handled in a way that doesn't distract too much from your other tasks.
I'll continue to think about the best way to do this in the future. Does anyone else have ideas on how this could or should be accomlished.?