If Clan Reinforcements had majored on improving the underperforming Clan mech chassis rather than boosting the already powerful top 3-4 Clan mech chassis, there wouldn't be such a groundswell of "Clans are OP".
But when they make the SCR, TBR, WHK and DWF even better than they were already, and a couple of those were basically the only mechs seen in CW anyway, it just made things worse.
On top of that, IS Quirks Pass Two nerfing the 9S, 6K, and other popular IS builds, was the salt in the wound for IS players.
And so here we are, with the best Clan mechs likely to get nerfed because of that chain of events, likely leaving the Clans with a full set of mediocre mechs before the dust settles
So if we look at back at what's happened, we see a series of mistakes by PGI:
Instead, if Clan Reinforcements variants had been done properly, the outcome could have been:
Truly, before Quirks Pass Two and the Clan Reinforcements variants, we had a pretty decent balance between Clan and IS. Both of those things upset that balance.