First, thanks for these two great plugins, they’re game changers.
Second, I would really hate to lose Theme My Profile. The difference between implementation of the profile page in both your plugins is important – TMP is the only plugin available whereby one can readily customise a profile displayed in the front end of a site, and all without hacking the core. For instance in the job I’m currently developing, I’ve done away with the aim / yahoo / jabber since none of my demographic would have a clue what they were, and the biography field because it doesn’t fit the site and is unnecessary. TMP has been indispensable, and TMLi wouldn’t have been able to do that.
If you’re really keen on the modular route, might I suggest the facility to switch parts of the profile display on/off?