Imperial Seal sounds like a decent upgrade compared to Mastermind's Accquisition.

Would you mind to explain your wincon?

Sure, I have 4-5 different win conditions in this deck. First is Mechanized Production. Pretty self explanatory. Second win condition is Approach of the Second Sun. I have lots of tutors and fast mana to find this card and cast it twice very fast. Third win condition is infinite turns and milling opponents with Temporal Manipulation, Duskmantle, House of Shadow, Soldevi Digger, and Planar Portal. You take an extra turn, use Soldevi Digger to put Temporal Manipulation on the bottom of your library, Planar Portal for the Temporal Manipulation back to your hand, and activate the mill from Duskmanle, House of Shadow. If you have enough mana, this is infinite turns and milling of all opponents. The fourth win condition is just using Jester's Cap to remove all cards from opponents libraries that would stop you from winning. You can Soldevi Digger or Academy Ruins the Jester's Cap back to your library and Planar Portal it back to your hand to repeat this process. I've made many players scoop their cards when I exiled all their removal from their libraries. The fifth and final win condition is just simply never running out of cards. You have Soldevi Digger to constantly put cards from your graveyard back into your library. It's not the prettiest or fastest win condition, but a valid one. I can normally win on turn 8 or 9 without too much trouble because I have so many tutors and fast mana in this deck. I hope that answers your question.

Thanks for explaining!