Actually, in-game, it helped Lucca out emotionally, even though it did nothing to affect how she fought, or anything.
Besides, what are you implying? That it should be Future Lucca's fault that Lara is crippled?
Indeed, it did help out Lucca emotionally, in fact, it was one of the most impressive moments in the game (especially if you pulled off saving Lara), but think about it, that gate came out of nowhere, and Lucca was able to rectify a terrible accident...imagine if she made it worse. Time became a tool at the team's disposal, I'd love to have seen them fuck up terribly somewhere and
not be able to fix it. You see these long-lasting decisions occasionally: saving Fritz, the various decisions that affect Crono's trial, and even saving Lara's legs. But even with all those decisions, there's one option to basically do the wrong thing and one option to do the right thing, and the effects of those decisions reflected the options themselves (as in, choosing the right decision gives you something good). Now imagine the impact of making a good decision with good intentions and it yields a terrible outcome...it would be a grave lesson in tampering with time, a lesson that may have been hinted at in CC.
Depressing as it is, I think it would have added depth to the game. But that's just how
I would change CT.