These kinds of changes can work though. It's more about process/testing. EU 4 has a long history of it, though. I feel the same way about the switch to ZoC forts, which still doesn't work properly. Not "quit the game" over it, but that it was an extreme change to a core mechanic around which the AI and game systems were not built. To this day, there are still significant flaws with the system, which I've detailed elsewhere.
Other major changes were unit pips per tech group, creation of "primitive" status, autonomy, and completely reworking buildings (monarch point cost, ducat cost, interaction with development).
Some of these I consider to be functional-to-good mechanics, or at least better than those they replaced. Others have never worked properly since their inception.
But yeah, you can find quit threads like this on game forums that are very old. Such threads are probably not much younger than game forums in general.