There is a clear incompatibility between how Cannon likes to play as a striker (runs in behind, going one-on-one with the GK), and how the team is currently instructed to play offensively (clear focus on working the ball into wide areas for deliveries into the box, patient build-up play, minimal interest in direct passing in behind a defence). It's possible that we would see more success from him were we to play in a manner that benefitted Cannon's constant movement along the defensive line (and in behind it). But instead, a significant expectation is placed on our strikers to be a link-up man, enabling the philosophy of moving the ball out to either side.
In the right side, I think Cannon would be significantly more effective than we are allowing him to be. And Preston, with Hecky in charge, could very well be that side. But unless we adopt a major change in tactical approach (which I suspect would also require a managerial change), Cannon is likely to always be ridiculed on here for poor performance. We'd be better off trying to get any sort of transfer fee for him just to mitigate the significant financial investment we put into his transfer in the first place.