Chris Hughton is a nice guy, a gentleman and in his day a good and respected footballer.
It is perhaps unfair to describe him as a 'good' or a 'poor' manager because there are many factors to be considered. As far as I can see, and looking at where he has been in position as manager or head coach, he has never really been tested in terms of managing any club at top level with the level of resources where he would have been expected to deliver results in terms of trophies and league position. I exclude EFL Championship where he had decent success but, in the Premier League with Newcastle, Norwich and subsequently Brighton, he clearly was constrained by finance and accordingly found himself struggling to maintain club status, fighting relegation year on year. The obvious result of under financing generally results in performances becoming more and more defensive due to the normal high cost of strikers and the whole thing becoming harder and harder as finances become more and more limited hence the same problems recruiting defenders.
Although I don't know the full circumstances, I was a STH at Brighton during his tenure and watched on as he struggled to maintain EPL status but eventually the owner decided enough was enough and he was replaced by a manager who favoured a more attacking style of football and Brighton have moved on somewhat from the CH era.
Whatever else I wish him (CH) well in whatever he does next.