I've played with these changes on PBE and while that's an environment with swingy games, the changes don't feel bad, or make the game feel alien.
The 'death turrets', as casters love to call the inner turrets, are a tiny bit easier to hold. Dragon change is nice imo. The buffs help, without being overwhelming, though if you're able to get 5 dragons they become pretty nice and make you feel good for basically controlling the dragon.
Crab seems pretty pointless. He just runs around and you feel silly chasing him. Can be nice though if you take it right before baron or dragon for the free vision.
The buff in the river is nice, but nothing game breaking. It's mainly there for split pushers honestly.
Baron Buff is not really weaker. You lose the regen, but your minions become a lot scarier. It's kind of fun 'protecting' your super canon minion, as he slowly wittles away the enemy inhib turrets from outside its range. It also feels good if you're losing to get baron and then have stronger minions helping you push out the super minions / lanes in general.
Haven't played in the jungle personally, but from what i've seen they don't seem to have broken the jungle.
Still haven't seen anyone build the new items yet, so can't comment on those.
Boosted base stats also aren't that big of a deal. It's basically compensating for the changes to regen on items. I could still go oom and I wouldn't regain health at crazy speeds. It seemed fine to me.
Most of what you're saying reminds me a lot of what we hear every season. Last season people freaked out about vision changes and adding new jungle camps, and while it made some big changes, it wasn't game breaking by any means. So far these changes (which Riot has said are very experimental) don't seem that bad. No point freaking out before they even iron out the details.