I agree about using multiple columns. Or perhaps it could be done via a nodelet? Then people could easily turn it off if they do not like it.

A nodelet is not enough IMHO. I think a sort of "mandatory", comprehensive, toc/daily best on top would be the most effective tool. But then certainly, it should be possible to turn it off for those who don't like it. Call it a "horizontal nodelet", if you like!

Another possiblity would be to have a summary page, listing categories and recent activity (titles and date).

Well, we somehow have already something like that, under NN and RAT, so adding a third thingy would be mostly a repetition, and not likely to help with the subject matter being discussed here, since both of those appearently don't either.