I've seen plenty of lineup scenarios around the site, and few if any mention Yunel as a serious lead-off candidate. I realize his RISP numbers were great last year, but I believe McLouth and possibly even Prado would be as productive in the #6 hole given their superior slugging percentages.
Add to this the fact that Escobar's on-base skills are superior to any other lead-off candidate, and it seems like a no brainer. You are putting Escobar in a position that maximizes his best skill, while allowing you to move McLouth and Prado (more on this further down) down in the order.
I would also bat Heyward 2nd in the lineup from Day 1. His on-base skills appear to be behind only Chipper and maybe Glaus on the team. He seems to make more sense that Prado or McLouth in this spot unless you think its too much for him to handle.
Back to the original argument, I realize this will basically boil down to everyone's though on whether hitting RISP is actually a skill. I'm sure most will agree Escobar is a good lead-off candidate, but many will want to see him down in the order in order to use his RISP "skill".