Playing with tracking can be interesting - trying to make uke change his blow, so he more or less unbalances himself. Needs timing, though, so when training slowly "no tracking" is a must I think.
Like most aikido concepts, a "correct/committed/competent attack" means very different things in different schools. If one does like one is used to in an unknown place, one might find more or less beginners patiently explaining why the way of attacking one was taught be very senior people destroys training completely...
I prefer uke doing tsuki so that he is in balance after finishing the blow. Have seen other variants, though - and in those cases, I think tsuki training is training on a body launching towards you rather than a strike.