I hope you aren't criticising the squad there. Your view matters not one jot so you need to be backing them.
But really, he hasn't changed tactics regardless of who we are playing. He is meant to be known for his defensive nous and we are conceding left right and centre. Grind a couple of results out defensively, then start to adapt it. If he has got some results, he has got himself some leeway to start becoming more expansive. It doesn't need to go from a defensive set up, directly to an expansive set up. There is middle ground.
He should be able to have us beating newcastle.or Burnley without playing defensive, so why would results tumble if he has ground out a few results and he then starts to tinker with it?
The issue is, we have no discernable style of play. We aren't defensive or expansive currently. Even when we had a full squad, for large portions of games we didn't look like there was a solid plan.