So one could say this is biased as I just hatched Ultimadragon from a Rare Egg, but the more I look at it and the kin it grew up with the more I feel like this monster could indeed use, albeit small, a buff.
Ultimadragon, Galliodragon, Heavenswyrm. These were the premier Legendary Monsters that were upgraded of the SE Stun Flash/Survivor monsters. Gallio and Heavenswyrm have both been buffed in recent updates, with Stun Flash becoming Stun Wave for Heavenswyrm and both receiving Harden Carapace. As far as I can tell, Ultimadragon is the only one of those three that has not received any love since inception.
That being said, it IS a Stun Immune monster so I understand why Devs and Players may hesitate when the idea of buffing it comes up. I wouldn’t suggest anything radical, just slight modification perhaps.
Heres my thoughts:
Option 1: Stun Flash becomes Stun Wave - similar to Heavenswyrm, this gives his Stun option a bit more oomph when it actually does go off as opposed to the 100s Stun Flash it currently has.
Option 2: Bloodthirst becomes Bloodcrave. Having the low speed, currently Ultimas only option to kill is utilizing Swift Cannibalize. Bloodrcrave on a 35%ish speed monster whose only way of charging said move quickly is by killing one of its teammates is not detrimental in any way, and would give Ultima some more deadly weapons to play with instead of waiting around and using uncharged Double Survivor and Bloodthirst to pass time.
Option 3: Replacing Ultranova All with a better/lower TU move. This could be as simple as replacing said move with 70TU Slayerbane. Ultimas attack is not the most impressive so it wont one shot everything with a Slayerbane move, but it also gives it a low TU option to try to nab kills and charge Bloodthirst in a more roundabout way.