Allow for single use Transmog tokens to be awarded from the loot table of raid bosses in a similar vein to the Frost token incentive like 25% chance it drops from certain bosses. Whilst this would be detrimental to the 'blizzlike' quality of the server I feel like enough changes have been made now where this feels like a natural step.
I would suspect that this would increase participation in all raids and legacy raids. Obviously the token should be gatekept perhaps after RS10/25? Or on par with the frost token? Could even add a bit of flavour and have the transmog NPC in the haberdasheries of the major cities. So it's implementation is not some obnoxious massive dick hanging around a high traffic area.
The transmog should also be of consequence so it would be a permanent change.

Feel like this could be good. I to agree with the different rates exp, proffesion, nightmare event, mounts from shop that this is something that would fit in our second home.
And that it wouldnt decrease the blizzness we have on this server.