I've thought of this gametype before, but you do run into some major issues with a LOT of abilities that are kinda interdependent.
- Sej's permafrost
- Cass's crap
- Kennen's passive + w (technically everything else too, but not necessarily)
- Fiora's ult + passive
- Darius's ult + passive
- Quinn's well, yeah, bunch of passive/ability linkings.
- Okay, how exactly do transformation abilities work? i.e. Elise/Nid ults?
- What about energy/mana/health/zero costs?
- I'm not even gonna ask how the heck animations work out ("INCOMING LULU WITH DEMACIAN JUSTICE!")
I think the last point is the deal breaker. Unless there's some easy way to detach signature animation elements of each passive from the champion they belong too. You might be in trouble depending on how LoL's programming/graphics architecture handles this.
Now onto the hilarious possibilities that may ensue from this:
- Veigar q passive + Karthus = GG
- Oh my gosh why did you replace Soraka's E with Zil's W.
- Best solo-combo engage ever: Panth stun + Naut stun + taric stun + Ekko stun + that ult that stuns people, uhhhhhh... oh yeah, bear time.
- If you give Fiora silver bullets, I swear...
- If you give Yi Sion's passive, I swear...
- Nasus is clearly redundant. Delete him. Give Poppy his q. Done. Also... cower in fear.
- Because Sion needed Tahm's ult passive... the Titanic just wasn't sadistic enough yet.
I'm just gonna keep adding to this list as things come to mind.