if he fought pac again without a catchweight he might be able to do better, but yeah, mayweather makes the most sense.
chavez jr? i doubt that. top rank has been extremely careful with jr, giving him very small steps up along the way, and cotto would be a HUGE step up over anything jr has ever faced.
i just dont see any other fighter that makes financial sense for cotto.
its not worth it for him in this stage of his career to take any unnecessary risks.
and well i agree with your assessment of top rank protecting junior (who doesnt?) i think he might do better than you expect.
for two reasons:
1) he IS improving. not saying he is as skilled as cotto but he is definitely formidable.
2) he is naturally bigger and has a decent chin.