OW is more complex (outside of high ranks). In many cases the changes are meant to balance characters so more combinations are equally viable. when i played TFC way back when, pyro was a worthless character, effectively unused for years. they eventually balanced him; so probably just the far higher number of characters and abilities and desire to make more things viable. OW is gets stale at high elo but at lower ranks it’s whatever people are best at that tend to work within reason. (i quit just before 2/2/2. played silver to diamond)