I think the pacing of TMP is fine, whereas 2001 is a crashing bore. Although that's probably because the slow parts of TMP have great music to listen to, while a lot of 2001 is just tedious silence. I've never liked the way Kubrick dealt with music.
While I think the pacing of TMP leaves much to be desired I can agree with you on 2001
. This is one of the most over-rated movie in existence.