Does anyone notice early game tank stats being noticeably weaker?

Ever since the assassin patch came out, It really seems like damage has just gone up across the board. Maybe Riot needs to even things out after adding Lethality and reworking champs, I don't know.

I play ARAM almost exclusively. Like 2-5 games a night. I noticed a stark difference after the assassin patch came out.

I played pure tank Amumu a few games ago. Like totally tank. 21 armor 72 health and 12 mr. 12/0/18 with CoC keystone. I was tanky. The only "offensive" items I had were hextech belt and Sunfire. Even not being focused directly, as the Garen was diving and tanking most of it, I was taking a lot of damage per hit. It almost felt as if none of the magic resist or armor was counting for much. This is very different from pre-patch because I would play the same build as Alistar and be able to walk up, take plenty of hits to slam and then head but someone towards my team and not be even remotely close to dead. Now, as Alistar, I die just as fast as I did with Amumu. I feel this way about pretty much every champ. Something is up with damage calculations, I believe.

This is not some QQ because I lost a game and I know this is just circumstantial evidence, but after 20 games, I feel like something is up.