According to meddler, corki is going to receive some buffs along with tristana, vayne and kalista.
The nerfs to hextech sharpnel 1.1 bonus damage,Q base damage and Trinity Force crippled corki and removed him from the meta. The aa-Q-aa combo lost 24 damage at level 1-2, and more at levels 3-6. His burst was arguably too strong, but right now he is just too weak.
In order to become a viable adc pick, I think the passive must be looked at. I know riot doesn't like to revert changes, but some adjustments to the passive could work.
Here are some idea's for corki's passive:
1. 104%/106%/110% AD at levels 1/6/11 (half magic, half physical). Some people suggested this change, because of the nerfs to TF. I think this could bring back corki mid, but it's bad for the adc role because he still can't build penetration and deal somewhat effectively with tanks.
2. 110% physical damage.( benefits from sheen and crit effects)
I think this change could bring back adc corki and open up some build paths. Right now there isn't any item corki synergize too well besides trinity force.We could see a variety of new builds with items like ghost blade, black cleaver, last whisper or bortk if this changes goes through.
3. 100% physical damage + 10% true damage(doesn't benefit from crit, benefits from sheen). Same as 2, but the flat bonus true damage fits the mid game power spike adc niche.
4. 100% physical +10% magic damage(benefits from sheen and crit). With this change corki can use some of the AD items more effectively and still fit the magic damage adc niche.
Overall I think the change to make corki's passive deal physical damage instead of the split damage would be really great for the adc corki players and could potentially bring him back into the meta game.