Personally, from what I've seen, I think he could add a creative aspect to our midfield that we're currently lacking, but most importantly of all, I think he could also be the answer to our high pressure problems too which have plagued us at times. Admittedly, what I've seen on him is quite limited though in comparison to Modric who I feel like I can make a full judgement on.
I just don't trust Jones as a midfielder though. He's the perfect example of what is wrong with British midfielders in a way: a lack of ability to play there, but praised for working hard and running around like a headless chicken. He has no positional sense, something that Carrick is good with as well when he's in the centre of midfield.
Jones isnt a midfielder though, he's just been deployed there occasionally. I wouldnt trust him in a midfield role either which is why i want us to sign a player there.
Regarding Martinez, i dont think we'l sign him, not now anyways. He's just very similar to Carrick i believe. SAF wouldnt play the 2 of them together. Modric would be a great fit to partner Carrick but as i said, it'd be incredible if we went into the season without any cover for Carrick. If we want to compete on all fronts, that'l be just stupid.