Dont recall wind dragon being special. Light mystic dragon was way harder for me than the others though.
Anyway, those pirate dragons seem pretty awful, which is typical i guess. Hopefully the chasers drop reasonably well. Imma have to waste bag space hoarding some for suzaku =p
Wind dragon is cool because green is the main dragon color, thanks to ADK. Light Mystic dragon was more annoying for me than hard. I could do it, but it would take forever, and every time I took something to speed things up, I'd die.
Pirate dragons aren't too bad. Their base stats are comparable to samurais, and their active is actually useful. Their cost is a bit lower too. If you're going to farm for chasers, I don't see the harm in skilling one up, it might be useful for a random conditional. Actually, the red one is pretty nice for that, since water sub attribute.