Aerodactyl is already a perfectly fine revenge-killer (though it has no priority attacks, but Jolteon doesn't either), so making Jolteon a revenge-killer seems unnecessary and a waste of a team slot. In fact, I don't think Jolteon is good for anything in UU, so I would suggest simply replacing it with a scarf Magneton. Also, how does removing roost make Crobat bulkier? Sure, taunt is a good move, but roost is also necessary. If you want to use taunt, then the best thing to replace would probably be U-turn.