The system seems nice. You can control where the power cap is, while creating encounters that are how you intend them to be because there is an upper limit in power stacks.
However, since people love to maximize dps, are you sure that people are not just going to go full power and speed only, or power and critical hit, and let those be the only two buffs that matter? I'm just asking if you have ideas for how to further make people want to go create other builds instead of just going for the tried and true damage combos. Honestly, from playing tons of different games with metas like this game has, I'm almost starting to wonder why players are not just given all the damage and other powers outside of skills like the cells in Dauntless, and instead the only skills that we can use and change are defensive skills that changes how we dodge, take damage and so on. It is only a thought, but it seems to me that *that* kind of system would reward players playing their own way much more than trying to copy whatever someone else does simply because it deals more damage. But maybe that might take too much build freedom away from the people who already love to fully spec those extra skill slots with chonky tank skills that makes the player only take single digits of damage.
The stack system does seem more intuitive though, I'll give you guys that. Like was written in the post, it is easier to let the behemoths deal debuffs too to the player. Honestly, would be really cool to have a behemoth where its main gimmick is buffs, and it will buff itself. But when it buffs itself, all the players get buffed too. And the other way around, it will debuff both itself and the players. You could easily create a mud or slime attack too, where if one is hit, one temporarily looses 4-5 stacks of speed. Or just go straight down to -5 for example.
For an actual question though, how are you going to go about creating three new cells for each and every gauntlet season? There are already so many different cells, and they keep getting slightly more confusing and less rewarding to get for each new set we get, so I was wondering if you are able to keep this going, or if you were going to put more effort into other aspects in the game. Creating new cells is nice for the build diversity, but the new cells can easily drown under all the existing ones if they serve the same main purpose as an already simpler to use one.
Can't wait to see what more you will cook up in the future though. The game is already pretty good, it just has a tendency to get stale in the long run due to the grind (and honestly, the hunting grounds made that grind feel even more like a grind. It is both really nice and at the same time really tedious, so I am glad that you are looking at adding pursuits on the side instead of replacing the hunting grounds entirely). Also, I hope to actually get to explore more ancient ruins and buildings too int the future though, the umbral (de)escalation is my favorite piece of content in the entire game.