Yup, minion block is deadly in any lane near the edges of the river on top/bot. the problem sometimes is when they follow the enemy and stop to attack them, if you're too close to the wall with them they leave you trapped sometimes till they move, die or you desperately flash the hell out of there.
I think the raptors in the jungle make that happen as well if you pounce in with nidalee in cat form. those raptors sometimes close you in perfectly and you need to pounce right outta there if an enemy comes sailing in.
I'm definitely not a fan of it. Espescially when there's a huge wave, they'll lock you in if there's a crowd around you as you go up the lane and they stop. it's just enough that the enemy can freely AA you with range and run outta there while you sit and take the hits.
Any time Two waves bundle up I give them a wide berth now until they fix on an objective, and even then they become a literal wall as they surround the target.
if it's a thing Riot done on purpose, I'm not a fan of it. your own allies shouldn't be able to kill your mobility in that way.