might be true, but if you had flash (another point i criticize, because flash is always necessray, except for kassa and tryn :P) you could flash in right in the centre of the teamfight after you tank runs in (and possibly causes some heavy cc) and deal MASSIVE damage, no matter to your squishiness. i often scored triple or even quadrakills while i was dead

and please, enter more images in your build ;) like Defile for example

well it's right that great AP might seem to be the best way to optimize the passive but if you're squichy (as a lot of karth) you'll be taken down by a carry at distance and your passive will be avoided easy. I really feel more powerful and useful when i can handle a whole teamfight with steal respectful damages!

i still think that deathcap is worth it. its definetly not bad to get about 200/300 extra dmg with your ulti, you´ll not miss it... 500 ap are fine but 800 are way better... although you spoke to this point in the guide i contradict ;)