Would have been a great fight, lot closer obviously. Chavez having a lot more success at actually nailing Whitaker, maybe the younger sweet P even more physical going on the attack? No kds but exciting to watch. I'll say Julio by split decision win.
Whitaker improved from the first Ramirez fight. He learned to use what he had and control the action.
In 87/88 Chavez may have been quick enough and Whitaker not as mature enough for Chavez to get on top and win a decision, maybe seven rounds to five.
I also have Chavez squeaking this one out by a close margin. I am guessing that it would be a very difficult fight to score, with lots of shifts in momentum. Both men were ATG fighters. And, this would likely be the best weight for both. (Although Whitaker had better success at the heavier weights)
I'd pick Whitaker over Chavez at any stage, really. Just got the wood on Chavez in terms of styles and he was even more formidable at 135 than he was at 147 (although I'll concede that the latter still suited him better than Julio). See no real reason to think that Chavez could reverse their 1993 fight and I think a fight a few years earlier would have looked pretty similar, maybe a shade closer. Whitaker by 3 rounds or so.