Gueye is a better version of Phil Neville, who was boss at what he did and nothing else
Every team needs a spoiler, someone who can break up what the opposition do and give the ball to someone good, which is what Neville did and what Gueye does - the main difference with Gueye is that he can also do a bit with the ball every now and then.
He's one of the few at the club who should be kept around at the moment.
Your are undervaluing Gueye. Phil Neville never came close to putting up the sort of defensive numbers that Gueye does, nor was he able to cover so much of the field.