I will look at it, but I think I prefer my last revision. It is not a 5e norm, but I think I am ok with that. Unlike most of your suggestions, I just don't see yours as an improvement. My version may be non-standard, but it is clear, simple, follows the flavor and the math works. I am pretty sure your option fails on the math and it doesn't fit the flavor. I also don't like how the dragon can't use its breath weapon again until a Rest. Why would a dragon every do this?yeah 5e really really simplified flying rules, and all for the better. Those kind of complexities are just not needed in the system.
I think the idea that buffet is an attack that consumes movement is fine, but you don’t need to add in things like “move x feet” or “must land”, those types of flying motions were left behind in 5e.
on the sustained breath, for a vanilla dragon, on average the dragon will get 1.66 breaths in the first 3 rounds and still get all of its legendary actions (and there is a 9% chance it gets to breathe in all 3 rounds). So I think bumping it up to 2.33 breathes in 3 rounds should not break the bank, especially if we remove the risk of getting lots of breaths continuously and consume legendary actions. So how about this.
Sustained Breath (3 legendary actions, 1/rest): the dragons breath weapon is recharged. Once used, the dragon cannot recharge its breath weapon until it gets a short or long rest.
in theory the ideal way to use this is:
2) .33% chance to recharge.
3) use sustained breath and breathe