Gunblade is too expensive, and post-nerf it kinda sucks. I'd prefer the cheaper route just getting the revolver and the alternate build item for LL. She also has an innate heal. Learn to harass. :P

I'll add to optional items. I agree that if you really want it it's not too bad. I'd actually say the better option would be to get Zeke's Herald.

you need to have gunblade for the life steal and spell vamp

By all the build i have tried for kalye this is the best one yet.I have note lost a single game with this build. My fastest game to win was 11min. with no surrender.

Voted up to your guide, Ionic spark is not fun on Kayle it' s just great, you shouldn't underestimate the power of that new item. The problem of your guide is the Instability of early game. By just taking a doran's ring and starting directly the on hit system will lead you to a non safe start with just 50/50 chances on success.

Check out my guide and my opinion in how to counter the item instability of Kayle.