If blood elf druids were to happen, I think it is very,
very unlikely that they would be introduced in Mists of Pandaria, but it would be very nice if it did happen some day.
Lynx Cat-Form running around Eversong Woods,
pweeeaaase Blizzard!
Obligatory Pro-Blood elf druid Info (even if some of the 'evidence' is from the RPGs!)
EDIT: Also, I've always thought the root Zael suggested a couple of posts above is perfectly viable and perhaps even more viable with the gradual political thawing under Lor'themar's regency, post-Kael's betrayal, where the Farstriders seem to have more weight to throw in public discourse than the magisters!