Worst issue so far? Nah, I'd still give that acclaim to issue 2. Although it's a close run thing, and still nothing for this issue to be proud of.
There's not a lot to add beyond what you've already said. It starts off promisingly enough, with the tale of how the Autobot B-Team (K-Team?) ended up on Cybertron, and then it does indeed all rapidly plummet into the toilet from there. Tension between the two groups of Autobots would have been fine, but this is badly written. And the human focussed stuff is just badly written.
The first climax, which finally reveals what this has all been about, was just disappointing at the time. We'd had so many stories featuring the Matrix as the focus of the villains' obsessions that this felt like it was going to be another case of just retreading old and well-worn ground. Along with all the other well-worn ground it had already been dragging us along. And given where this part of the plot goes (at least initially) it seems like they had no idea what they were doing with it, either.
As for Drift, yes, he's certainly a non-event here. But as a reader, I was also certainly already annoyed by him at this point just because of the amount of hype he was getting. With so much focus on unlikeable human characters and the Transformers characters that I did like getting such short shrift, the last thing I wanted was to be introduced to another character that I was expecting to be badly written and that I wouldn't care about. So that was certainly not the best decision that IDW ever made.
So yeah, five issues in and my will to care or continue with the series was certainly waning by this point. If not for the reveal of the Matrix and being mordibly curious as to whether or not they'd actually do anything new and fresh with the idea, and if not for the promise of Maximum Dynobots on the horizon I would have been very tempted to abandon the comics at this point. Which, I'm guessing, is not the result they were after.
Stuart Webb. Who knows everything about nothing and not a lot about that.
Action Force/G.I. Joe