If you want more out of the deck, there is always Thought-Knot Seer. It's great at any point in the game due to hand attack that's usually limited to black and red (but is even more useful since it exiles instead of discards), it has as big a body as Roon, and since you have Roon it can be repeated, its leave the battlefield clause can help you gain an ally as well! Also if you're going to run infinite combos, I don't see why you can't go to more degenerate extremes like playing a stax centric infinite combo deck with an aggro backup plan. Defense Grid, Propaganda, Stonehorn Dignitary, and the Thought-Knot Seer are good stax pieces. (that's if you are amused by the stax idea)

I think you could cut down on dorks if you played more basics and creatures that enter play and look for basics, like Solemn Simulacrum or Farhaven Elf. It also dissuades Blood Moon and Back to Basics, but that's just my two cents.

To Nathanial: I would play the Leyline over the orrery since Roon is blue, the moment you have one of these two they defeat each other's purposes. Besides, leylines come into play for free if they are in your opening hand, so unless your opponent's have enchantment removal on hand, its going to be harder to get rid of, especially if he plays stax Roon of the flicker puns!

I'm considering adding more land ramp because it's more resilient than rocks and dorks. I'd probably run Wood Elves first because it can get nonbasics and they come in untapped (I'm not that concerned about Blood Moon because I have dorks and a decent number of basics/cards that search for basics) and Solemn Simulacrum next. I don't want to cut the dorks because of their explosiveness, but I might cut the fast mana rocks to maintain power parity with my playgroup.

As to the stax part, I've run anti-aggro cards before and the one I've been most satisfied with is Spike Weaver because it synergizes with Roon but doesn't need Roon to be repeatable, unlike Stonehorn. I've also tried Defense Grid but I prefer countermagic as combo protection because it lets me interact with my opponents' plans too. Thought-Knot Seer is probably solid in 1v1 but single-target discard isn't very strong in multiplayer and I don't think the payoff is worth the cost. I kind of like Propaganda though, it discourages random attacks and makes it really hard for people to kill me through combat damage. I'll give it some thought, thanks for the suggestions!

Well, single target discard does suck when you are the top threat at the table. I do believe that the single target discard is very powerful for what it is, it doesn't make everyone exile and reveal, so everyone isn't pressured. And its "drawback" can keep you and the seer alive longer, with the added ability to take away a board wipe/threat from an opponent is very strong, especially since its exile and not straight discard. If anything, thought-knot seer is more for punish, and its a very good closer against one person since it just dominates in this style of deck since there is no good way to play around a creature that's nigh unkillable and takes away your answers. But that's my two cents, and my final words on Thought-Knot Seer. If you don't like the card, I won't force it.

If you liked Propaganda, then you'll like Ghostly Prison and Norn's Annex. If you want more cards like that, I recommend Scryfall. Its SO much better than gatherer.