You know what would be cool?
If themed gyms got defensive bonuses (except normal types), that's what.
So if a gym only had Pokemon from a certain type or color scheme or all of them were dinosaurs/dogs/fishes, all defenders could get a bonus on either of their stats in battle.
That way, we could dethrone normal type Blisslaxchans from being the only viable species and push for a more diverse environment and team play.
Imagine an eevolution-themed gym giving a big bad stat bonus to the Eevee, sort of like an Extreme Evoboost from Sun &Moon (it would still make Eevee worthless but it would be worthlessly cool).
Also, I think a system like that would work best if all Pokemon in the gym benefited from the boost but said boost became higher with each Pokemon comboing into it.
So, of course, the first Pokemon lined up in a gym would get the biggest benefit from the theme boost because there would be 5 other mons boosting it from the get-go, but it would also set the theme for other players to combo along.
Coordinated groups of players could pull this off in seconds and it would make gyms a little bit more fun to challenge IMO.
I thought of this because I just realized how tired I am of seeing Blisslaxchan in gyms. I am sooooooo tireeeeeeeed of them.
Thoughts?