I've been playing League for a while now, and I've realized that while I do know what a good mid laner is out of the champions available, I don't actually know what classifies a champion as a mid lane champ. If anyone has any ideas, or anyone knows for sure, I'd like to know people's thoughts on the definition of mid lane champion.
It varies with the meta and with who Riot buffs or nerfs. The key qualities you want to look for are kind of all over the board though.
One flavour of mid laner is the high kill pressure roaming mid (Diana, Talon, Fizz, Zed, etc). Another is the incessant wave-clear and siege mid (Kog'maw, Azir, Ziggs, etc). Yet another is the supportive mid laner that loves to group with their team and enable other carries and/or set up wombo combos (Orianna, Lulu, Lux, etc).
Obviously a bunch of these attributes overlap in different champions and they all have their strengths. Generally, though, you want the following things: ---Can 1v1 ---Has decent gank assistance or gank followup ---Can remain relatively safe from ganks (this one is really optional; people like Ori and Kog have a terrible time vs ganking junglers.)
All that said, though, mid is really, really matchup dependent. That's why you have people like GV Keane who seem to be willing to play almost anything mid. It also heavily depends on junglers on both teams. That's why you have teams that are famous for camping mid, like TSM. At the end of the day, any champion is good mid as long as a) the matchup is decent and b) the jungler either ganks or pressures.
What makes a champion a fantastic mid laner is having largely favourable matchups and not requiring as much jungle assistance. This is why we see things like Viktor, who has a cancerously low-interaction laning phase, exceptionally good wave clear, very strong poke, and tremendous teamfight damage (arguably his only weakness is skirmishes against multiple threats on open space).
