I don't believe that's really helping the problem. You just leave all the older units to die in the dust while only this unit in particular shines.
You can give them as much speed as you want but if you don't have the weapon skills to back it up, it's mediocre offensive at best.
The problem is that all inheritable dragonstones are defensive:
The most popular inheritable dragonstone is Lightening Breath and that's purely defensive. Forget about using it on offense, especially with the +1 special cooldown.
Dark Breath is... niche at best and not very useful for most dragons. It's also another defensive breath.
The most recent inheritable dragonstone is Glittering Breath and that's also purely defensive. Not to mention locked behind a seasonal unit.
Sure, IS can just keep putting newer dragons with unique breaths that are more offensive but that leaves the older dragons in the dust. Or even our most recent f2p dragon, Bantu, comes with Dark Breath. And I'm pretty sure that if someones has a +10 Bantu, they use Lightening Breath and enemy phase only just like Adult Tiki.