New Health Regen

Has anyone else encountered tremendously broken HP regen? I was just playing Lissandra top against a sion.. The only MR he bought was merc treads. He first built ohmwrecker, which I wasn't too worried about cause no MR.. Until I quickly learned that his health regen plus his built in shield, was allowing him to regen/tank more damage than I could do to him. He was healing at almost 100 HP every 5 seconds or so I watched it tick up at one point, it was asinine. My team told me to build a morello but I told them I could never get him to 40% HP. in the team fights we won, we never killed him. We killed all his partners, and then he just walked away.. Eventually we lost cause he just got so much HP, he even built a warmogs and that just made his HP regen even more broken.

Now I don't have anything against HP regen in the late game, I get that, it's fine. but in the laning phase, he was out sustaining me with HP regen. He didn't build any lifesteal or MR focused items, just armor, HP, and hp regen. You shouldn't be able to build ARMOR against an AP caster, and never die.. That just doesn't seem fair to me. Am I alone in this or?

And I get he could have got a spirit visage and owned me at that rate, but he didn't he built armor.. That's what's annoying me so much.