Runan's is strong, but you're sacrificing crit and damage to get it, so I'm ok with that trade off.
I don't mind warmogs.
Some of my friends say Bulwark is silly because it's so good it's a 'must buy' which effectively limits one players itemization. I don't see it that way. I think anyone who mains support likes getting items like that, even if they didn't random a support champ. It's also a nice balanced (gives 3 stats) defensive item for pretty much any melee. I think it should stay as is.
BoTRK should be implemented for sure. I see bruisers like Jarvan, mundo, and amumu that are indestructible late game while still doing insane damage b/c they have a % damage ability.
As a caveat for the Rioters that are dropping in and reading: it's very hard to get a good feel for item balance without matchmade queues (not saying "WTF riot were iz our queues???", just being real). I fought against a team that bought 3 early warmogs the other day, but we still won pretty easily. Because I'm usually in a premade with other friends that are like me (~gold elo, can play a huge pool of champs well), we are a bit shielded from some of the disadvantages many people have in arams.
Player skill is nerfed as a measure of success in ARAM, but in the long run, if you simulate 10,000 games of team 1700 elo versus team 1300 elo, the results will be pretty lopsided.