It's no about that. It needs testing, but it's also 'safe' and not controversial. Most stuff in DF won't cause uproar that cause dev watercooler that cause new iteration of system that cause bigger or smaller uproar that cause dev watercooler... it could last month like with soulbinds.
Only thing that has potential for that is dragon riding, Blizzard could came out with something grindy and stupid here that will require more iterations. But for example I think testing stuff like new renown style reputations will be easy.
Another thing is that Blizzard were always far from efficient during Alpha/Beta, in Legion it took months to even launch all specs. So there is room to improve. We will see, without first few Alpha builds we can't really judge.