I’ve been questing/using my cards pretty much as I’ve been getting them. Doing my daily missions/dungeons. Didn’t get slowed down in the slightest around 170 so I have no idea what people are talking about. I’m now 217, just finished the 215 zone and there are no zones between 215-220. Maybe we could get a couple zones (like 217 & 219) with some quests thrown in? 
Thanks for the great game, IMC!