This is an interesting thread. Two issues standbout.
1 Is Harris up to being our manager
2 Can he change our style of play?

On the 2nd question I dont think he can while he has the same players. IMO he would be just as well reverting to the type of play the team has been used to for 3 years. It was noticeable yesterday our best spell came when we stopped trying to play football and played long balls and pressing high. Until Harris brings in at least 3/4 of his 'own' players the team will not change the way it plays.
2 Is Harris up to managing a 'big' club. It is beginning to look like that he is not. Clearly he needs to be given time, and as has been pointed out this is beginning to feel like a Slade like appointment, but I have serious doubts as to whether he is going to be here long term. Millwall may be his level.