Silencing Sona would have no effect.
Teemo vs Lee Sin would also have little effect.

Cho'gath becomes weaker as he grows.
Basically, the bigger he got, the slower he would move.
http://tvtropes.org/pmwiki/pmwiki.ph.../SquareCubeLaw

Singed would eventually die from his own poison after breathing it in too long

Pantheon, nidalee, mundo, sivir, kat, shaco, shen, akali, kennen, jarvan, gragas, draven(without q up), ziggs, heimerdinger, twisted fate, and sejuani would need a backup weapon. Kogmaw would eventually kill himself because he empties his stores of everything liquid inside of him frequently. Floating champions would fall to the ground when stunned. Tryndamere would 1 shot everything. Wukong's ult would hit harder than Garen's e. olaf would only have one axe until he picks his axe up. Most ranged carries would eventually have to go back to the summoner pool because they run out of ammo.

Wukong would start with 16000 AD, 1 AD for every pound his staff weighs.

Katarina can't aim her ult worth anything because she's spinning wildly in a circle and can't exactly see who she's throwing stuff at.

Miss Fortune takes 20 seconds between each attack to reload her flintlocks.

GP couldn't use oranges to repair his blindness or any other cc.