Isshin commander help

im looking to make the deck more synergistic without adding expensive cards. im going to have to take out the tutors and the tomb, mana vault to get it to atleast bracket 3 for casual commander night. so is there any cards that arent on the game changers list that will make the deck more synergistic. Also is there any changes to the mana base you would make?

moxfield url

https://moxfield.com/decks/MiyQiksuU0y1dtubLYy0FA