I don't see how that would be the realistic outcome here. If we'd assume that they get the balancing intervalls down to 1 or 2 weeks per iteration, then there would be absolutely no point in changing classes that often since you couldn't equip them anyway in that timeframe. The biggest hurdle here is A) simply to actually touch on all classes equally and not play favorites and B) that the class gimmiks in WoW have more relevance in content than in overwatch. Breaking the rofl-lol-Rogue meta in WoW for M+ is quite a bit harder than adjusting Mei's icewall duration by a few hundret milliseconds without destroying the ability/gimmik entirely.
Edit: Also you just described the current balancing situation. They change things once a tier and depending on the fact if your classes' code monkey bothered to submit changes or not and how they turn out you might as well reroll. The only reason why we see so little class changes atm is because of the fucked up damage distribution having shifted a large chunk to non-class specific gimmiks in the azerite system.