One of the problems I have seen in GBL is how weighted it is towards bulk. They did add CMP being based off Attack but that’s only useful in very limited situations so I was thinking of ways to add spice to the game and make different kinds of 'mon useful.
My thought was making the countdown timer tied to the attack stat. This could work out in a couple ways, but the idea is that attack-heavy 'mon could switch in and out sooner than bulky 'mon. Think about it: Snorlax needs a nap after battling but Haunter can jump right back in! I think this fits nicely with the theme and could add in a fun strategy of keeping at least one glassy 'mon on your team to add flexibility. There could be good reason to use a Gengar instead of Jellicent because you can swap him out at 1hp and swap him in as a “3rd shield” or switch in to take a positive matchup (e.g. swapping in to Medicham who might not be able to switch out in time).