Is there room in LOL for a Mesmer style champ?

Going all the way back nearly 10 years ago, in the age of when WoW was released there was the mythical game called Guild Wars 1. It didn't have the 1 back then. In it there was a very unique class called mesmers.

It's not too hard to explain what they were in terms of gameplay, but they were considered a support type champion whose primary role was to counterplay other classes. Without going into too much detail, they were very good at locking down one specific thing if set up correctly. However if you didn't bring the right skills for an encounter you were screwed. If you brought a few skills for everything you'd have a little effect all over, but nothing huge to bring down one foe with. In MtH terms they were very white/blue in their ability to answer others.

A final note on their gameplay - they were a very difficult to learn to use and set up, but once you learned them, they were a very easy class to play. So a LOL mesmer style champ would have to be a character you aren't just going to do well in the beginning and need to invest time in.

Thematically, they were broken up into illusion, domination, and inspiration. Gameplay they focused on things like hitting the other teams mana, interrupting skills, punishment skills, health degeneration, and basically a lot of stuff that took you down indirectly. You even had options for stealing an enemy's skills or increasing his cooldowns. Now you could point out leblanc and while she certainly has an illusion thematic, with the loss of the silence, she doesn't really fit the overall role and theme of a mesmer, even if she passes the eyeball test.

Now, I really liked domination mesmers, though without hexes a character designed for punishment seems harder to pull off. The only way I can think of doing it is a champ who's ult lets him flip skills (without another model). One group might have more damage based on your targets AD and Armor while the other would have more damage based on AP and MR.

The other option I see is a character who can not only deal damage, but also hurt the other team's mana. Take something like Chaos Storm (it was bad for most of GW1's life). A small 3 second AoE effect that not only dealt damage, but hurt enemy's mana bars would be interesting. Or energy surge would be cool. One foe takes damage and loses mana and every enemy near him takes damage. Something like visions of regret would be cool, but I don't know how that would be pulled off. A champ with a silence would be almost mandatory. Something that's a cross between diversion and wastrel's demise would be weird, but riot fun. You either not use a skill give up health to keep your cooldowns the same or if you use a skill, it gets a big CD penalty.

I'd love to see an interruption effect but I'm not sure how it'd work in LOL. Maybe a shield that if hit by a spell, negates the spell while damaging and silencing the attacker, but if you hit someone with an AA you are blinded/damaged but can still use spells. While I'm getting off-track it's not technically Mesmer-ish, a champ with skills that let the enemy pick how he's getting screwed seems like something Riot should try. MtG just tried something like that in the form of tribute.

Finally I see a few inspiration skills that'd make good passives. Lyssa's aura would be fun, but that's been tried in SOADA with Vexie so the numbers need to be right for it to be usable. A modified form of tease would be fun too. Enemy skills cost 5%-10% more mana and that extra cost goes directly into your mana bar. Or maybe something simple like channeling where every time you cast a spell, you gain or steal 5-10 mana from every nearby enemy. The defensive stances could also be used as a passive. Take physical damage, you get +20% AR but lose 10% MR, and vice versa for taking magic damage.

To a non-rioter like myself it seems like you could get the basis for 2-3 champions out of these ideas.

@Riot @Morello @Meddler

PS. Mods - I'm posting this discussion here not because I'm saying here's a champ idea, but I'm wondering if this style of character would be doable in LOL mechanically.

PPS. To everyone saying Leblanc I'm talking about larger mechanical issues that GW had.

PPPS. I don't want to talk about GW2 mesmers.