Chulane, Teller of Tales
1) No, I'd run
Arcades, the Strategist as your commander. I know a lot of people enjoy playing "secret" commanders, but the problem is that, to find them, you generally have to get lucky or use tutors. I see
Summoner's Pact and
Eladamri's Call in your list, so I'll presume you rely on the latter, then you're wasting time tutoring a card (Arcades) that you could have just used as your commander. Chulane would be great in the 99, and is great overall, but looking at your creature selection, you're going to want access to Arcades every time - Chulane is essentially a great draw spell. Taking out those tutors and replacing with two spells that are useful in every situation seems like a better choice to me.
2) Usually decklists have a number of lands included in the list. For those reading, it's currently 33 lands, and I see 3 mana rocks, three land search spells, and a few mana dorks. I'd definitely go higher on the land count, maybe aim for 37 assuming your other rocks/ramp/dorks stay the same?
3) I'd probably include
Wave of Reckoning as a generally 1-sided boardwipe.
Thwart seems way worse than a whole host of spells, Actually a few of your counterspells seem subpar in multiplayer EDH:
Mystical Dispute,
Tale's End, previously mentioned Thwart, I'd probably rather just use something like
Heroic Intervention. Your deck wants to essentially flood the board with dudes, I'd include more board protection: I already mentioned Heroic Intervention, but
Cosmic Intervention is also good. You have
Solemnity plus
Decree of Silence, cool combo, but with only one way to tutor Solemnity (
Muddle the Mixture) and zero ways to tutor Decree, I'd probably just play cards that are better in every circumstance.
4) You didn't ask about this, but your title misspells your commander's name ("Arcadis"). I'm not sure if that's on purpose or not, but if not, then it's an eyesore and might otherwise not get people to look at your thread who might otherwise look at it. I'm thinking when people come to MTGNexus, search "Arcades, the Strategist", and then never find your list because you typed Arcadis.