I wouldn't say a sub is necessary and could be perfectly happy listening to them alone, but sounded from your original post you might be looking for something more in the bass range so hence the recommendation for the 25s. I heard the 22s in a fairly large room, but you have a pretty small room so the 22s may well satisfy.
I would characterize the 22s as neutral, and not in a sterile, cold way but rather in a very natural way. Brightness is always in the ear of the beholder, but I didn't find the 22s bright at all -- just nicely detailed. But again it's their ability to disappear into the music (and room) and throw off a transparent holographic stage with superb imaging that I find most impressive among their many impressive traits. Hope this helps.