Puzzle Solved..I Think

I have been confused for a while now. After saying at Blizzcon that players will have access to all their classes' specs in Legion, various barriers to spec switching have rotated in and out of the alpha/beta. We have artifact weapons that restrict switching specs. Then, for a suspiciously short time, there was the old-school gold cost for spec switching. About an hour later Blizzard had a post ready to go that removed the gold cost, but added a required reagent to switching individual talents. Think, Tome of the Clear Mind, but much more expensive and not available from a vendor mount.
I have been baffled. As a BM hunter who primarily raids, I make 1 or 2 talent changes in a night of raiding. I couldn't figure out why Blizzard thought this change was necessary. I never find myself waiting on people to change talents. Looking at twitter and the bolgosphere, it seems I'm not alone. This seems, according to the overall voice of the community, like Blizzard "fixing" a non-problem. It was perplexing. Then Fiannor at Misdirections commented on one of their posts about Mythic+ dungeons, and it all became clear to me. Swapping may be a non-issue NOW, but in Legion ..
I speculate swapping could become a problem in Mythic+ dungeons (if you are unaware, dungeons in Legion will behave like Diablo rifts). I would absolutely switch between BM and MM when going from trash to bosses, for example. Got the debuff that puts out constant damage? No problem, throw on Spirit Bond! Movement increase between packs? Heck yeah! I finally understand why Blizzard has been trying so hard to lock us into one spec via the artifacts.
I can't prove it, but I absolutely convinced Fiannor was right. And this is crazy. Blizzard is going to break the best version of the talent system they have ever had over one small aspect of the game that frankly nobody asked for. When I want to run a Diablo rift, guess which game I launch? Diablo. Anybody who wants that style of play can get it. Hell, most of us WoW players got it for free from the Annual Pass! If the current spec and talent system really will break these Mythic+ dungeons, they should just make talents locked WHEN YOU ARE IN THE DUNGEON! I imagine that is what they would really prefer, but technical issues compounded by a release date forced them to create this convoluted "reason" why we shouldn't really change specs and talents. Well guys, figure it out. This proposed system is ridiculous. Here is MMO Champion's data on how many people did endless proving grounds (the closest thing we have to Mythic+). Maybe we don't need them at all..