Even with a two man mid we could use more quality on the bench, but buying another rotation player at a similar level to Stu, Asa, Lemina seems somewhat pointless. We needed someone who can push the starters for a place and allow better rotation without such a stark drop-off in quality.
Rincon isn't that. I guess he's just a numbers-replacement for Hernanes, so we can have the option of using a 3 man mid, and have injury cover.