Bissouma was given a limited role because he was absolutely top notch in breaking up play with interceptions and tackles, but not so good with his passing and shooting. He can do more though, and if we had not recruited so well, more would have been asked of him and he may have become even more...
Andrew Crofts, Elliot Bennet, Dean Hammond, Leo Ulloa, some were loans but none flopped, Crofts was awesome till injury ended him.
Edit: Where we have had problems is returning Managers being way below what they achieved first time round with Micky Adams and Allan Mullery.