I think both are good: meaning both jitte and sofi and I think it comes down to which one you like better. I personally think jitte is better so I would play than sofi.

I kind of like revoker and my buddy and I were talking about it earlier today actually even before I read your post so I find it funny that you just mention him. He seems really good and I am going to try him out.

Kira- it is a bomb with sower but by itself I just do not like it. It also makes your equipment not as good imo. I understand why you have it there but I feel you must have sower to make it good. It may be my play style but I hate paying 3 mana for it when I don't have sower. or it gets stifle or counter.

Spellsutter- I like the fact that 7 of my creatures of flash which can have surprise factor when I have jitte on the board. I think jitte is still by far the best equipment. It does everything that I want it to be. gain life, kill creatures, and pump making it awesome for us. I also like the fact in the late game I can bounce spellsutter with jace and use him a again. i like having that option.

Sword of feast and famine- Never thought of it using it. seems pretty decent

Morphling- yes he cost 5 mana or more to protect him but let me say this. HE IS A BOMB WHEN HE HAS JITTE ON HIM. i played a lot of games today and I would say about 65 percent of the time If I was in a losing side he made me win just because the power of jitte. the ability to untap, protect himself(if you make him so he can't be target of spells or abilites you can still pump him with jitte since it doesn't target) and still pump himself with jitte is bonkers good. It ends the game so quickly and you will win every attrition war. Today I face down 3 gofy and I had morphling with jitte and beat 3 gofys just to show you the sheer power of what it can do. For me I love it and I think it is a bomb and is my trump card. Some people don't like it but I am just explaining why I think so highly of it.

Right now I am using 3 jace since I run spellsutter..clique..and sower since I like bouncing them and the fact that he is a win con. I can see playing 2 though, but for me I think 3 is a good number

Counterspell- this is def a 4 of in this deck. Nothing else said about it.

The only reason why I might run keg is if I see a lot of affinity. I actually hate that card though lol

what do you guys think of terferi I personally do not think he makes the cut but I could be wrong about him.

I think vs merfolk I would rather have llawan and prop vs goblins over sofi personally but that could just be me. I have been very happy with this main deck so far for this deck. I just need a good board, but I will say that there are so many times where I wish i had back to basic main has it would have won me so many games today, but right now I do not want dead cards and vs some decks that card does nothing so it goes to the board. Keep coming up with more ideas guys since I think MUC can now compete and do well again.