In general, it sounds as if you are describing a horse that is very self focussed. I mean, not that he's stuck up, but I mean that though you are riding him, or lunging him, he is not mentally connected to you. Thus, he pretty much stays in his own mind and deals with things any way he feels necessary. If he doesn't feel like moving, he doesn't put much into his canter, if he thinks he needs more rein, he pigroots, if he feels that he is going down the road by himself (without a confident leader) then he will be reactive and frightened.
All of those things would lessen or go away if he were more mentally attuned to the rider. Being that he's only five, he is still a "baby" in a way. So, his attention span will be particularly short. Your job is to learn how to cue him into you more, But that also means you have to be more cued into him.
This is very general "advice" so not really very valuable. But it is true that pretty much all those issues are due to him not having a mental connection or dependence on you for leadership.