you dont want Zhonya's Hourglass against AP lol thats for AD... you should recommend Banshee's Veil against AP = Magic Resist for Mid lane. Im sure that's a type-o on your end

if you are against katerina, have fun shrecking.

This is nice...
I have played Fiddlesticks a few times in Mid lane and I love it.
Roaming with Fiddlesticks is no problem since most of the times they don't expect you to roam in the early stages of the game ( Let's say around level 3 and 4 ).
The movement speed quintessences also help me with catch up to people.
It was also funny to have a Zed coming close to me to kill me at 100 HP just to get silenced, feared and drained. I actually made one rage quit in Ranked :^).
Laning is also not a problem if you're good at dodging ( especially with the movement speed from the runes and passive and later on also from the boots ).
It's always funny to see people trying to dive me with champions like Lee and Yasuo and then end up dying, because of the E bouncing and me just regeneration from them. x)
And not to begin about the ultimate of fiddlesticks...
If your enemy is not aware of you hiding behind the wall, then you can just ambush him or her without any problems.
Anyway, it's a really nice guide & build folks, you should try it out for yourself.
Cheers lad. +1

Do you ever get a bit nervous people are going to report or call you troll for going mid with fiddle?

I find it better to max E first. It gives you great poke and waveclear. I also find that Fidd has great sustain in lane with Drain. Another + is that most mids have no idea how to counter you. I destroy pretty much everyone mid.