title says it all,

and when I say mage I mean like ranged ones, not kassadin.

Morgana.

Morgana is almost always banned. I can see how she can be a problem, but there does not need to be such a stigma about her.

Zyra is commonly banned lately due to her extremely high burst potential and amount of CC (slow, snare, knockup).

The only other ranged mage that I have seen banned was Ahri. Assumedly due to her high mobility and charm, which is quite possibly one of the most irritating disables to take in the game.

All-time? Heimer... lol well ok just early S1... he was banned literally every game for months and months... it took riot 5 straight patches of nerfs to finally kill him (and they killed him GOOD...).

Morgana ranges from extremely hard to impossible to counter in lane... at her very worst matchups she can still sit back and farm better than practically anyone else can when they are winning. Late game, she has very good damage AND extremely good utility, some of the best in the game. She is definitely one of the better mids.

Ahri more just because she is a good counter to a lot of mages in lane... her assassin-ish nature means she can often open up on enemy mages pretty fearlessly with the burst, mobility, and cc to really wreck their squishy asses if they aren't very careful (and sometimes even if they are) and unlike a certain other ap assassin mage.. leblanc, she doesn't turn into complete garbage later on; late game she continues to have a lot of utility with her cc and very decent damage.

Zyra. I have no opinion on... personally I never thought she was too powerful, since I never had problems with one. I found her easy to zone and her damage to be very avoidable whenever I played against her mid.

karthus

Why would you give morgana such stigma? lol @ that. Morgana can completely zone out almost any other mage. Plus when with most mages, cc is the way they get their kills, would you believe it if i told you morgana has a shield that makes her immune to cc? (brand stun = kill, anivia stun = kill, annie stun = kill, lb silence = kill) i think i make my point that she is immune to all of their combos in most situations. Also on top of that, a jungler relies on their cc to have successful ganks, oh morgana shield. No ganks for mid anymore, making it a 1v1 all the time in which she always wins.

Not counting Kassadin,...

Morgana
Karthus
Zyra before Nerfs

Love it when Morgana still gets mindlessly trend banned when there's far more deserving bans for mid lane.

(Morgana was banned all of once at gamescon, and want to know what every game she was picked in had in common? the team who had her lost the match.)

Bans are usually this ... 1-2 tanks... 1-2 bruisers... 1 support. There are better bans than mid mages most of the time since they are easier to counterpick/play than most of the other champs people ban. For example tanks, if played right, generally have an excellent chance to get their initiation move and cc down effectively in most teamfights no matter what the other team does, or what their composition is, which is why tanks are common bans... supports likewise, because their contribution to teamfights is also hard to counter with just team composition or good play. Morganna, you can just be aware of her shield, relatively short ranges and easily blocked skillshot cc and make her a lot less effective. Bruisers, it comes down to their team disruption and cc capabilities usually.

Morganna's a good solid mid, one of the better ones, but still rarely worth banning if you know what you are doing unless she specifically counters your team somehow.

But kass is a mage...?