Nebulous
Legend
Would this take into account the dragons xp budget though? Like if a human wizard were (somehow) a solo, he probably wouldn’t have bonuses against being knocked prone, etc. so are we proposing dragons just naturally be a better solo for the level? (not a terrible proposal, mind you). Actually, it occurs to me that dragons have hover flight, which means they can freely fly at all times, and I believe there are special rules for knocking prone a creature in flight. Does anyone have a more encyclopedic knowledge of the rules?
I do NOT have encyclopedic knowledge of the rules. But...
I don't think the challenge of the solo is being changed, so much as rebalanced to be more fun. The goal is shorter, scarier fights that the PCs still win (barring bad luck, bad tactics, a mean DM, etc)
As for a stunned flying dragon, i would think it crashes and takes significant damage.