Well I play AP Kennen as my main, and I would like to know if I should get dodge or amor seals for my main ?

Armor seals reduce more damage than dodge if you have low armor. Dodge seals are better on tanks and anyone who buys large amounts of armor, because both dodge and armor have diminishing returns (and dodge is very hard to buy). So on AP Kennen, the clear choice is armor.

Also, so much is undodgeable in the game. TF's cards, all 3 of Xin's strikes, Gp's Parrley...kind of annoying.

So yeah. I'll do the math out if you ask nicely.

Thanks guys I guess ill go with flat amor seals.

If you are against physical champs who rely mostly on auto attacks (tryndamere, yi, ashe, vayne) the clear cut choice is dodge. Now with the new tenacity items picking up a ninja tabi and foregoing mercury treads would be a very viable option against auto attack champs.

you can't dodge turret shots (see what I'm saying?)