You might even get more than four mana, which is kinda nuts so early in the game
As for the deck itself, adding cards that reduce the cost of casting spells is always a good idea, and a lot of them like Jaces Sanctum come with an upside that might synergize well with the deck
The quick mana offered by Sol Ring can allow for explosive starts, and while it has long been a staple in the Commander format it is currently restricted in Vintage and banned in Legacy
Unfortunately a mana value of 5 restricts it to Limited play
Here are ten staple win condition cards that I look to when doing new builds: Craterhoof Behemoth Description : Craterhoof Behemoth is a creature that grants all your creatures trample and +X/+X until end of turn, where X is the number of creatures you control
The mill ultimate is neat but doesnt really synergize with the rest of the card, though cards like Sphinxs Tutelage and Psychic Corrosion can turn the draw from its front side (and lets be honest, youre playing blue so you will draw cards) into some library damage