Bato, Thief of Wits [WIP]

My idea for a champion is Bato, Thief of Wits (open to suggestions on his epithet) is a ranged champion with no weapon (like karma), who uses mana as a primary resource. His mechanics surround the copying of an opponent's (and/or ally's) abilities with his ultimate. His ultimate would be available from Level 1 and is the ability that allows him to replicate abilities from other champions. Similar to k6's evolution mechanic, using it It would open up his Q/W/E to fit a replicated ability when leveled up at level 6/11/16. At level 16, Bato has the option of replicating the ultimate of another champion, if he chooses.

As for how it would play out, I'm currently thinking you would target an enemy to "lock" your target, and press the ability again a short time after any of their ability casts, to copy their last cast ability.

So you activate your ult and proc a champion with a debuff. At the same time--akin to k6--you get to select a slot (Q, W, or E), that the new ability will go into. While in range of the debuffed champion, and for a set time after the initial cast, you can activate your ultimate a second time, to steal the last ability cast by that champ. You cannot cast the ability a second time until you have chosen a slot for the ability to go into. The last cast of his ultimate should be channeled, or otherwise highly vulnerable to interrupts/cancels, given that it is the only time Bato can replicate an ultimate. It would be channeled/extra vulnerable no matter if Bato replicates a basic or ultimate ability, and the ability he replicates will replace his own ultimate. (Can't steal any more abilities, choose wisely)

Potential Drawbacks:

I was thinking that maybe He could only replicate abilities based on range or type. Only skillshots, only ranged casts, but I feel like that limits what he's able to do, and the right (or wrong) team comp would make him a human-controlled auto-attack minion.

Given his initial weaknesses/mechanics as they stand, he would be pretty much stuck as a support-laner, with roam potential based on team comp. Possibly top lane if we fix up his pros/cons.

He can't replicate abilities that use a different resource pool, OR he can replicate them, but the cost is converted to a health cost like Aatrox's abilities.

Cannot replicate certain abilities that are weapon-dependent (like Olaf's) or certain self-targeted buffs that are weapon-dependent (draven's axes)

But CAN target vague/general abilities that are not weapon-depentent, including self-targeted buffs (Diana's shield, possibly projectile skillshots like Ashe's)

Example: Bato can replicate Darius' W E and R, but not his Q, as it requires an axe. He can replicate

Doesn't scale abilities like normal champs. Can only scale abilities on "replicated slots" each level-up. Leveling up allows ultimate to be cast cast to replace an already-opened slot. until 16, which will ALWAYS replace his original ultimate itself

Can't replicate ultimates until 16, and activating his ultimate for the 4th time will replace the ultimate itself.

This is all I have for now. I'm open to suggestions, tangents, and fleshing out, as long as he can keep the name Bato, and we stick with the idea that he can copy an ability (which I realize might not be technically possible, but maybe for the future, once coding allows for it, if it's not possible now). Collaborate with me :)