Dragon improvement ideas

While I think having more dragons is a good idea, providing stats is not necessarily is, since these stats have different synergies with champions. Imagine if there is 50% chance to buy a rageblade in the shop, and you are a yi or jax player. If you are lucky, you are too strong, otherwise you are useless. I usually prefer champion neutral effects like that part of baron buff which makes minions stronger. This buff is equally good for all champions.

What about adding extra abilities instead of granting buffs? E.g. the player who defeats a red dragon can bombard an area on the map which stuns all champions for 1s (a custom gangplank ulti, can be used once, and must be used within 4 minutes). A wind dragon grants a skill which reveals all enemy champions for a short duration (weakened form of twisted fate ulti). These skills promotes teamplay, fun to watch, gives meaningful, but one time advantage (you can get more if you kill more dragons). Similar to Corki Valkyrie.