I do skip some abilities but generally for practical reasons. If an ability is unnecessary and getting it would make a frequently used skill difficult to access (eg I'd have to scroll down to Steal for Rikku) then I leave it out. This requires planning who should have what, so not everybody needs bribe, spare change isnt very useful and so on.

However I have toyed with the idea of keeping things in character a bit. I don't like the idea of Auron stealing (beneath his dignity), and I ve deliberately kept Lulu's str down (though that was partly so she could use status effects and breaks without killing the target). It would be nice not to have clones anyway.