The reason those are a sin is because they are not optimal choices you made :P
Yes, it might still work, but no it is probably not optimal.

@abilities; Your ball is the most important thing as Orianna. You can only move your ball by using 2 spells, E (with 9 sec CD) and Q (with 6-3 sec CD). If you max Q, it gets a shorter CD and more damage output. That CD is necessary for QWR combo's. You also could do them with E, but that does mean you need an ally charging in (like Malphite or something). Maxing Q will grant you more control over the ball, which is important for Orianna :P

@Masteries; Fury is fun and all, and I am sure it helps you, but look at the rest. Summoner's Insight will reduce the CD of flash, very important. Runic Affinity will increase the duration of the spiderbuff, which also will help. Or you could go defense and go for Veteran's Scars , at any rate, the 9th point is worth it most of the time in masteries.

Ahh excellent, thank you!

That's helped me out a lot, I'll no doubt keep trying to update it despite the downvoting and sort it out, and learn some more code, the Executioner icon in masteries was literally me learning how to use it and trying it out xD

What's your reasoning behind sins two and three though?
This is how I've built her to play in this guide and I feel that I not so much need to Max Q last but HAVE to max W and E as soon as possible to make it work..

as for 21/0/9 I've never quite understood why that's done so often.. I don't see the relevance to anything in those numbers, my masteries are what's worked for me and taking points out of say Fury, to put in utility would be detrimental to her performance..

Thanks again though! that was a big help :3

Thy sins
1. No comment to vote
2. 25-0-5
3. Maxing Q last.
4. Minimal use of coding + structure
5. No example build in cheatsheet

Thy blessing
1. All basics included
2. Decent amount of content
3. Decent structure in cheatsheet

Result: Path of the Student
The main reason I didn't vote on your guide is because of the fact that comment to vote is not on, and you suffered 3 blows because of that.

I recommend putting C2V on asap, so if people downvote in the future, you have information that can help you make your guide better.

Also:
Try using more picturesque coding, like you did with executioner in the masteries.
It will help a lot with the structure.

Have fun :D