The central midfield debate is an interesting one, so I'll give my opinions. However, I'll preface it by saying this is a positive debate to have, no way should we be slagging off either player.
Slater and Robson are both classy, incredible players and any lower league team would love to have either one, so the fact we have both (for now) is brilliant. The problem is, is that they are both really similar players. That's why Hutton + Slater or Robson is an effective midfield two. Hutton is your ball winner and deeper midfielder that'll drop into defence when needed and Craig/Finn is your visionary man who will play the passes and look for attacking options.
When you put Slater & Robson together in a two, or part of a 3 man midfield. They both try to do that same job and inevitably stumbling upon each other. Considering that, it's then not surprising that since Craig's comeback from injury one or both of Craig and Finn have put in poor performances. If I had to choose one or the other I'd probably go for Slater as he has more experience but would be happy to keep both. As it stands with rumours circling neither of them will be at the club come August. Craig to Arbroath and Finn back to Dundee United, pushing for the starting XI but most likely a useful option from the bench for the Tangerines.
My preferred formation for the Loons has flip-flopped throughout the season but from now on and potentially going into the playoffs I'd play a 4-2-3-1 with Seb Ross number 10 and Hutton playing alongside Slater, as I feel that gives us the most balanced midfield. Hutton deep winning tackles, Slater (or equally Robson) playmaking and Seb being the attacking runner, supporting Ben upfront but also drifting wide to help Thommo/Flanny/Stef whoever's out wide at that point in the game.
Finally, I'll reiterate my original point, these debates are good debates to have, much better than last autumn where we unbelievably played Aitken and Harkins as wingers!