Each of our midfielders have different strengths. And that isn't a problem as such. Whilst Lerma is probably the closest we have to a 'complete' midfielder, in the modern game most central players stick to specific roles, even the very best midfielders at the very best clubs.
Real Madrid and Barcelona don't play 4-4-2 with two rounded central midfielders doing a bit of everything. It's a case of putting together a central midfield that combines those strengths in such a way to create a complete department.
Cook brings more imagination with his passing and a wider range of passing, than anyone else we have. Surman can do some of that, but Cook naturally takes more risks, and sometimes you need that to unlock an opposition. But sometimes it will result in possession given away and opposition attacks coming at us, directly resulting from Cook's marginally miss-hit attempt at a 40 yard raking ball over the opposition full back.
If you want lots of safe possession and intelligent ball retention, you turn to Surman. If you want lots of running and hassling, you turn to Gosling. Both credible options to have. But there is no doubting that our most gifted central midfielders are Cook and Lerma, and if you picked a full strength side that was setup 4-4-2, especially against a top 6 side (and the formation is a different argument to have) you need to pick Cook and Lerma.
Now how many games have Cook and Lerma played together? Half a dozen perhaps. How many games have Surman and Gosling played together? Scores. So the more experienced pairing will be comfortable and fairly reliable, if somewhat limited especially against the top sides. But we all know they will do the job Eddie asks without any massive screw-ups.
Lerma and Cook would make errors, goals would result from their miscommunication and misplaced passes. But if Eddie insists on a midfield two against better opposition than us, then when everyone is fit he has to risk the best two individuals. And if given enough games together, they would improve as a pair and that reliability gap to Surman and Gosling will be reduced.
In the summer I can see Kyle Taylor and Nnamdi Ofoborh getting the full first team pre-season, plus Eddie looking at another midfield signing as well. Especially as Surman turns 33 in August. Young lads and new signings are a risk in themselves, so there's all the more reason to give Lerma and Cook as much game time together as possible (once Cook is fit). And hey once we have a few more points on the board, why not see a bit of Taylor and Ofoborh before this season is out.
Our midfield cannot be pinned around Surman at 33 next season. He should be the experienced head on the bench and in the dressing room, who comes on to steady the last 20 minutes of games, or to partner one of the young midfielders through games when they come in. And that is in no way pinning our defeat on Surman, far far from it. For all the stick he gets (some of it from me) he's been huge in our PL survival these years. It's just an inevitable part of plotting our journey onwards.