Yeah I just don't think Allan is a natural sitting player. Maybe in a 3 (which is what he did when Ancelotti arrived) he could get away with it, but his best role is, like Longstaff, to press around and hassle the opposition, which is why him playing in a 2 doesn't make sense as it doesn't get the best out of him or Doucoure.
My worry with Longstaff is it's just another bang average player that this particular manager likes. And the results aren't good enough with this manager and I don't think they ever will be. Eventually he will go and we're burdened with Benitez's wants, just like we were with other managers.
The plus side with Longstaff is that he's young (22/23). But unlike Mykolenko and Patterson, I don't think he's got enough in his game to be particularly wanted by anybody other than Benitez.
That being said if he comes I'll support him. There's just better players for what we need (a sitter, or a transitional number 10) available even this window. Kamara from Marseille is a brilliant talent, available for around £10m as he's out of contract. A proper sitting midfielder. There are others too.
I just feel that bringing Longstaff in doesn't really solve the issues we have in midfield, but maybe Benitez would switch to a 3 and they'd muddle through.