I can see both points of views. I agree with most in that updates with physical change brings a lil excitement. 1.10 for example, igloos and polar bears....lets be real, they serve no real purpose, but as an adventurer most all of us packed our things and set out to find those new things. When they added ocean monuments, who didnt bail out in a boat in search for 1? Same will go for this new update, it gives us something new to aim for.
Now, for the other side of it. "Useless" things are what I dislike most about updates. I'm sure there's tons out there that just love the Llama, but really? A Llama? Out of all the animals that could be added, hey chose the Llama. Now will this affect anyones gamepay? Not at all, but what do we do with a Llama? Ride it? We've had horses forever, and I honestly dont know anyone that use those due to the mass amount of water in every world. But atleast if you're desperate enough you can kill horses for leather.......what will this amazing Llama offer?
Ok ok, so you can tell I'm not excited about the Llama addition lol. But the others, I'm ok with. Anything involving more inventory space, YES please. More variety of mobs and dungeons, meh there's good and bad sides to that. I agree with Candlevera that adding too many dungeons kill the "unique" world experience. It was better when you actually had to WORK to find a dungeon,now you can stand on a mountain top and view multiples within render distance. IMO it's like saying diamonds are too hard to find, so lets add 40% more ore to worldgen so people dont have to work so hard. When "finding" something new loses it's thrill because it's now given to you around every corner, thats when things are going downhill.
As with everything, the rest is arguable by each individual. Added potions, enchants, restone contraptions, commands etc doesnt affect anyone in basic gameplay. They can add 3 million new potions to tomorrow and I'll likely only use the same ol basics we have now, same with enchants etc. If it's not thrown in my face and forced upon me, I really dont care. I dont have to use it and somewhere in MC land someone is oving that item or whatever so it's all good.
And to end this useless post of mine, I agree that if these or previous changes (or even future changes) are that big of a deal, it's super easy to fall back to a version you're most happy with. And before you say "well there's nothing exciting to do in older versions" well guess what? Thats why the "update" exist in the 1st place, otherwise we'd ALL be sitting on the same old versions right now