So, like, I want to divert this conversation back to a point the OP made earlier. While it's fair to say "let's just play the game we can", and if it's fun to try to succeed in arena at an early stage, great, but I really want to emphasise two points:
1) It can get expensive very, *very* quickly. We're not talking just spending silver on upgrading gear - which is very expensive in and of itself. The rabbit hole that OP is looking to explore will, in short order, start involving gems for masteries, and then books for skills. And very shortly from there, it becomes "well this team didn't quite work, so who else can I try to swap out", and let's just continue this exercise until suddenly we're out of resources.
2) While doing all of that, those resources are not being spent in places that actually help progress. This is a game of exponentially-growing resources, and just like the whole "compounding interest" argument (that I particularly despise because of how simplistic it is), every time you waste something now, your longer-term returns are cut back ever more.
So if you really want to play the "let's see what happens" game, just try to do so with as little resource-investment as possible.
It's quite possible to explore team ideas without needing to invest deeply in them. For example, yes, booking that skill may take it from a 5-turn cooldown to a 3-turn one. But in an arena fight? You're almost never getting a chance to use the skill twice to begin with, and, even in the situations where you are, you'll be able to figure out if the team works long before you need to think about that.
Same goes for those skills that go from 75% chance to land to 100%. Like - yes, you want to be at 100% because you don't want to lose a fight to a weighted coinflip. But you can see how the team works without needing to do that. Then, if it does, you can consider if it's actually worth investing in.