I'm regularly seeing tanks and bruisers tank entire teams for 5+ seconds.

1v5. Somehow I just don't think this is healthy. Mundo's, Shyvannas, Rammuses, Illalois and hell, even Xin Zhaos. It's literally retarded, especially considering that all of those that I mentioned have high amounts of DPS and are capable of killing squishies really fast. Armour penetration fcking sucks this season. And while it may not be as large a problem in THE LCS, where they'll likely have at least one champion dedicated to tank busting - like a penetration Deathfires Brand or something, it freaking sucks in SoloQ where the only person you can really rely on is yourself. Currently every time I'm against a tank they stall the game out against my early lead, walk around with near impunity while being an absolute nuisance - if not an outright deadly threat to any champion that actually carries as a risk. Then come 30 minutes they bring the pain, either they stall team fights out for an excruciatingly long time with their beefy lol-I'll-walk-in-1v5-and-not-die selves, in which case you can forget about getting objectives even if you win the fight, or they'll advance the line so deep and so quickly with their absolute TANKDGAF attitude that you just get destroyed. Oh, and I hate ADCs this season too. Miss Fortune just LOLWAT dmg, and once ADCs hit 5/6 items, as an opposing squishy, you either OS them or you die.