Blizzard seems to have issues with their Ranking systems. Been an issue all the way back to WoW. HotS is majorly jugged. Hopefully OW season 2 will work better, but I'm not going to hold my breath.
And as for Felis Domesticus and their max-charisma build, it's important to remember that even before the gamebreakers became dominant enough to really be worth charming, they could get by just hanging out and taking advantage of their big grain stockpiles that tend to attract small rodents.
Now, there really are plenty of gimmick builds that don't work so well. Cheetahs maxed out sprint speed by sacrificing endurance and some other things, but it turns out a sprint-based predator build only really works in wide open plains, and even then it's no better than some other predators.
Yep. Gold hell is a thing. But the season is long, and with time (and some breaks, and knowing when to stop before you get into a losing streak) things might work out. Maybe. I guess.