On Irelia FOTM:
Irelia is FOTM @ mid-high elo ( I play at around 1.6k Elo solo ranked, so I would know, and regularly watch high elo europe streams) in europe ranked for already two weeks, and if you look at alot of the FOTMS, you can see that most of them first stemmed from the european server.
She is really, really good with trinity force and tank items - most people say she's Xin Zhao 0.5, but what Irelia has is a very sustinaible laning phase (More so than Cho'gath or Mundo - with her ulti she can heal 3/4 of her health every 50 secs, and on top of that she heals very quickly on minions with a bit of lifesteal and W levels) with a decent mid game with Xin Zhao-like burst - but she doesn't fall off late game like Xin Zhao does. Still does a lot of damage with her steriod, but is very, very tanky - she borders on what Tryndmare can do in late game if farmed, without the weak early phases.
It's not because HotshotGG says she's OP. It's because of her absurd amounts of damage combined with her survivability, and sustainability (in lane, and in pushes). She has a small lack of mobility, but thats why you have ghost/flash.
As for the best champions, it's hard to say. I'd consider the "best ones", the ones which are hard to counterpick, and actually bring useful things to a team. This is what you'll see on ranked first picks. My personal favorite is actually Ashe - she's rarely banned, but is a very, very strong pick - even in ranked. Intiation, perma slow, long range all wrapped into a carry is simply absurdly good - which is why I almost always pick her if I'm first pick.
Otherwise I'll have to go with Morgana for her godly black shield and support abilites (she's not popular anymore because she got some minor nerfs - I lol'd) and Cho'Gath for his pure ability to super tank games by having 4k HP at 20 mins, followed by some very nice resistances mins laters.
However, if you're the last pick, or counter pick, certain champs become a lot more viable. If you have a team focused on escapes on the enemy team, like Nidalee, Ezreal, Kassadin, Shen, Janna - then Akali becomes godlike - and Warwick almost useless - even though generally, if our mage was first pick, I'd prefer Anivia over Akali. So it really depends on the match you're playing as to what the "best champion" is. It's diffrent in normal games, where you have blind picks - but it's the same principle. Synergy with your teammates and the ability to counter as many strategies as possible is key.
