Regarding your plants thing, I have a suggestion.

You mentioned Magic the Gathering as a good example of RNG that you have some control over because you get to customize your deck.

You can do that with the plants too.

You can attach each type of plant (Oh, how convenient, there's three) with each branch of the mastery pages (Oh, how convenient, there's three)

such that investing into one mastery over another has an impact on which type of plant will show up more in the game.

KABLAM. The plants then become a controllable RNG element that make the mastery choices a hell of a lot more interesting.

They don't have to match the trees very well, I mean I know there isn't a dps one, a tank one, and a utility. But it would be very interesting to see a team that intentionally synchs up their mastery pages so that they focus on getting more peaches at the expense of obvious best-in-slot masteries.

Eh?