we've had a suggestion of running generation based gyms instead of type
It's been asked that I explain this. The idea goes as follows:
-R/B/G/Y Gym
-G/S/C Gym
-S/R/E Gym
-D/P/P Gym
-B/W/2 Gym
-X/Y/Later Gym
-Dark Gym
-Fairy Gym
The main 6 gyms can use any pokemon from their respective generations, while the last two can break the generation rule but must stick to one type, symbolizing light/dark but with no actual light element.
Whether these would be restricted to using only forms found in their respective generations or any forms of lines introduced in their generation (meaning no Pichu for Gym 2) is up for discussion.
Whether Mega forms would be given to gen 5 and below is up for discussion.
Whether Jigglypuff is normal or fairy is up for discussion.