Yes, anything that wants to take advantage of MIDI-CI will need revising. However, bear in mind that everything is backward compatible. Nothing you have now won't work because of MIDI-CI, but things going forward can if they decide to take advantage of it.
This is like much of the MIDI spec - a keyboard doesn't have to support polyphonic aftertouch, but it's there for those that do.
BTW "May is MIDI Month" over at
midi.org - I'm doing a MIDI-specific "Tip of the Day" over there during the month of May. There are also some artist interviews and such.