Varying the number of heroes selected each round of an unchanging L50 Gold+1 draft brawl… doesn’t actually provide that much variety. It would be more fun and interesting (for me at least) if some of the draft brawls were up at platinum or plat+X level and some were down lower, at silver anyways—a bronze or green draft might not have a whole lot of flavor.
Plat drafts especially would give newer players a taste of plat heroes and strats—and not just newer players, really. Even though I have 20+ plat heroes, that still means most of my heroes are not plat, which means an opportunity to play around with them as temporary plats might help with deciding who to plat next.
And silver drafts would give the newest players a chance to maybe use strats they’ve already mastered (which will break at gold or platinum) and force the rest of us to reorient, temporarily, to life without our almighty passive skills.