I think Rammus is a bit too strong right now.
As someone who plays a lot of Rammus, I think he straight up does way too much damage. Starting from when you get Bramble Vest, it feels too easy to simply 100-0 someone. Playing against him is kind of counterintuitive, because he does too much damage if you ignore him, but you also take a lot of damage if you attack him. Considering this, if you get ahead on Rammus, it just feels like there is nothing the enemy can do against you. I'm enjoying the freelo I'm getting out of the champion right now, but he needs a nerf.
(Here are some damage statistics from my recent Rammus games, as backup to my claims:
22.3k damage in a 28:56 minutes game, second most damage in the game was the enemy Tristana, with 18.3k damage. (10/3/18)
40.4k damage in a 39:13 minutes game, only behind my Lucian and the enemy Brand. (14/6/15)
18.3k damage in a 24:18 minutes, outdamaged by Azir and Rumble (both high damage squishies) and tied with the enemy Lucian) (8/5/11)