Some Observations About Winrates
At the time of writing, the top 10 highest win rate champions of the game are as follows:

And I want to point out some common trends I noticed.
For a start, a whole 6 of the 10 champions noted are Magic Damage dominant, further supported by that Janna is an AP Support and Volibear does Hybrid damage. The exceptions to this rule who truly do mostly physical damage being Trundle, Miss Fortune. Could this be a problem with Magic Resistance?
Interestingly, the top 10 are perfectly split between 5 Melees and 5 Ranged.
Most of these champs sit in interesting places on the damage Triangle. Brand and Malzahar both are primarily Burst Based Mages with some Anti-Tank and sustained damage qualities. Trundle, Amumu, Mundo, and Volibear are all rather DPS heavy champs if we consider them primarily Tanks. Rammus heavily counters DPS champs, his part of the Triangle's weakness.
There are 0 Assassins in the top 10.
Depending on your definition of a Fighter/Tank or Tank/Fighter, you're looking at nearly half of the top 10 being these Tanky damage dealers. Ironically, none of them are the 6 "official" Juggernauts that Riot points towards, so could it be a case that these almost Juggernauts slipped by while Riot focused on their more popular brethren?
Interestingly, all of these champions are from 2011 or are even older than that. They're also relatively immobile, as the only one with a dash or flash is Amumu's ability to drag himself to targets.
Just some thoughts and observations. How do you guys interpret the data?
jungle 
) but if you do, the AOE nuke or CC will push the champ over the top.
is frequently on this list for highest winrates in solo queue, and I wanted to address him as well for the same reasons as everyone else) Because they do REALLY well in solo queue scenarios where the enemy team has very little co-ordination. Need to set up an easy ace as Amumu? Q + R = Congratulations, you're in Silver 5. Mundo? It takes an entire team to take that monster down. Rammus? He can single out 1 person and give his team a good 10 seconds to come in and Shrek him up. Garen? Come flying out of the nearest bush, obliterate the accursed villains, and leg it from the other 4 nerds chasing after you.