This seems a good time as any for this suggestion, and for any that agree with me, please, PLEASE reach out to Blizzard on twitter because I don't has teh tweetz. This has been an annoyance for too long and this is our chance to get this fixed.
Please don't let allow druids to lose costume when shifting.
If I understand it correctly, Blizzard removed the druid ability to keep costumes when shifting in and out of forms because they felt that players could not tell what form druids were in. I feel that this was a very poor excuse and we suffered a very severe nerf that has lasted years because the 'fix' was poorly implemented. Players always had the ability to see what form we were in based on what resources we were using. If the druid has a rage bar he/she is in bear, etc. Additionally you could also see the form 'buff', so even if the druid had a mana bar you could see if he was in moonkin form, tree form or caster form.
We druids derive as much fun from costumes as any other player and it's a shame to keep us locked out of this feature for so many years.
What I propose is not for druids to keep costumes when shifting in form, but merely that we don't lose the costume 'buff' when in form. This way, we can shift into form for combat, and the many (apparently) players that had poor vision would be able to see what form we are in. Upon shifting to caster form we would still retain the costume buff! Brilliant!
We already have this functionality in game - see Caverns of Time instances, so this can't be much of a stretch/hard to implement. Please, allow druids to retain the costume 'buff' so that we too may rejoice during the many fun holiday events and enjoy all the costumes in game!