I can see it's based on Flood's build, but not much is changed O.o It's just a weaker version, imo.

"Shield takes 1:1 AP so it will be absorbing around 250-300 damage when you get the first rank at level 10." + point 7
I don't understand why you take your first point in shield so late. As you say, it blocks everything, so one point at lvl 3 or 4 could help a lot (if you could go to midd lane, lvl 10 is not a problem; else, one point should be put in it before).

Your 8th point is absolute truth ... but hard to execute (actually, this joins your 6th point).

Magic Pen for Marks ?

I also guess your Mejai comes really late. If you make one (i would drop it to put the Lich bane in the build again ^^), you have to benefit from all the possible stacks and it should be done first. Same for the Rylai, i'd swap it with the Void staff : opponents rarely have massive MR at the beginning, but you need life quite fast.

This would make : Mejai -> Sorcerer's -> Archangel -> Rylai -> Void staf -> Zhonya (last 2 swapable depending on ennemies MR).
Or : Sorcerer's -> Archangel (Tears before boots) -> Rylai -> Lich bane -> Void -> Zhonya (last 2 still swapable for the same reason)

Otherwise, quite perfect guide with *really* good and important advice :)