IF this is your wife's deck then she's a pretty lucky person. I do have some suggestions that may help the deck run a little bit better;
1) Adjust the mana ratio so that the distribution is equal to the cost. This can be done by switching around the basic lands, also I would recommend running at least 24 lands in a deck such as this.
2) Using your creatures effects to the fullest are what's going to make this deck run smoothly. I would recommend switching out the
dark confidant instead for creatures that have various effects such as trample and reach. If draw power is what you're aiming fr with that creature then you can use the B/G self mill cards that return to ravnica has access to and do graveyard recursion that way.
3) For spells you may want to work and focus on manipulating the graveyard more. It can prove to be a valuable resource. Cards like down//
dirty can give you recursion, If you use
burst of strength on
deathrite shaman then you can untap it and tap it multiple times per turn. The same can be said if you used
spidery grasp. Also
golgari charm would be good to add to the side board,
mizzium skin can protect a lot of your creatures when played right,
plasm capture is a counter spell that basically gives you mana back for using it,
psychic strike does wonders in any deck that has U/B ,
savage surge is another good way to untap creatures expectantly,
simic charm is a good multipurpose tool,
tower defense keeps many of your creatures
alive,
wildwood rebirth is good for recursion.