Adding Saheeli, Sublime Artificer to "The Riddler"
I believe "The Riddler" can benefit from adding one to two copies of Seheeli, Sublime Artificer for the following reasons:
After playing the deck, I found that the deck did not have a sufficient amount of creatures required to win the game in the vintage format when paired up with other agro decks. I looked at similar decks that do well with casting numerous spells in a turn and I found that Monastery Mentor worked well with Paradoxical Outcome decks as a win condition of overwhelming an opponent with Monk tokens. Though having Monastery Mentor in this deck would look good, I feel that the deck would not consistently produce enough white mana needed to cast Mentor even if additional white sources were added. Also splashing in white mana for just Mentor may not be a good idea. Adding Seheeli, Sublime Artificer to the deck would not take any alterations of mana sources. After testing this deck with Seheeli in it, I found that I had generated sufficient Servo tokens to win games against agro-heavy vintage decks.
Saheeli, Sublime Artificer's activated ability in combination with Time Vault is of great advantage. You can turn another artifact you control into an untapped copy of Time Vault and gain an extra turn with it. You can do this twice with a new Saheeli and you can even gain more than two additional turns by bouncing Saheeli with Paradoxical Outcome and replaying her. A couple of extra turns should be enough to win the game with this deck.
Saheeli, Sublime Artificer's activated and triggered ability in combination with Bolas's Citadel is an alternative win condition. Saheeli can generate a large amount of Servo tokens in this deck that can be sacrificed to Bolas's Citadel to make the opponent loose ten life. To make the opponent loose an additional ten life to win the game, use Saheeli's activated ability to copy Bolas's Citadel and use it's activated ability. There usually is enough leftover Servo tokens and other permanents available to sacrifice to the Citadel copy.
Saheeli, Sublime Artificer can be exiled to Force of will if you choose to do so.
Saheeli, Sublime Artificer can also be used to copy Hollow One on something like a Mox if needed or copy Blightsteel Colossus.
I believe that only one or two copies of Saheeli are needed since the deck has a massive amount of card draw.
Any feedback is welcome.