You know what? Guides are a representation of one's thoughts and ideas. If this is how the person builds Oriana, and if it works for them, I don't see any problem at all.

Why are you guys complaining how a RoA is so key to Oriana? If it is, then why don't you just buy it then? And In my opinion, a Deathcap is not a necessary item for all AP casters. For example, how Saintvicious uses Fiddle and Kennen proves it. He goes late on the Large Rod, and decides after whether to go Deathcap or Hourglass.

Also, from what I have seen, Oriana is a much better solo/duo DPS (good harass) than she is a support. Just saying...

Anyways, the core build and game setup makes perfect sense, and that's all that matters. I hope there are others who will understand.

you get your RoA way too late, I think fast Cata - Boots - RoA - Deathcap is the best combo.
nice combos section, but the item order imo is not very good

needs an RoA if u ask me

Well I didnt read that part, and I disagree with it. I did read, "After Core Items - Choice is Yours" Rabadon's is not a choice lol its mandatory with Orianna... even the AS/AD guides acknowledge this. I suppose its preference to pick a Rylai's/Banshee's over a Rod of Ages, but Rabadon's is not optional on any AP caster that I know of. I would even argue that Void Staff/Abyssal Scepter is core these days.

good guide only things that confused me are the masteries (2 points in critical? wtf?),
and maxing protect before attack. you need the combo q w for farming. (except when youre a support)
in whole, i like it.

No, no it is not. A one time DPS will do little to Harrass. Putting a green glowing circle which does AOE on the groun and speeds up you and slows the enemy WILL harass. Max it first as the guide suggests and after a few times fought in the Green Circle for slow and DPS, laugh as you throw your ball out there and the opponent tries to manuver around it versus get anywhere close.

THAT is harassment and minion kill prevention.

Rod of Ages>Rilay's on Orianna imo
And I think it's much better to max out her Q first and not W, especially while playing mid.. It's much more effective and easy to harrass with your Q (plus it costs less mana)

So buy them, problem?
I said you can buy anything you want after Rylai's Crystal Scepter (because I tested it and I have bigger benefit from it than from Rabadon/Rodo***es in mid game)
And when opponent team has a lot CC, you probably wont go Rabadon but Banshee instead, it makes sence.

Next time read whole guide plz, I mentioned both items you like, please, read it.

Rabadon's is a core item with Orianna and so is Rod of Ages.

Nice Orianna Guide