I think there is a point to be made there, he's simply not broad enough in his observation. In fact, maybe your gamescom impressions aren't broad enough in their generalization either, and
tuluse is actually right - this is all a problem because game previews are a weird editorial form that inherently gravitates towards mirroring publisher PR. I mean, for all intents and purposes, the previews you and Gragt wrote, for Logic Artists and Larian respectively, were informative, exhaustive, and fair. The problem with them is that you're ultimately just reporting what the developers show and tell you, with no way to verify it. You can ask pointed questions, and they can answer to your satisfaction, but there's no guarantee a particular feature will ultimately make it into the game, and this isn't through anyone's ill will (look at the SRR gameplay demo vs how that mission looks in the actual game).
There's really nothing you can do about this. You can strive for a neutral tone and refrain from describing how nice the people you met were, but that doesn't change the content of your piece in any meaningful way, and that content is unilaterally determined by the developer and publisher.
So maybe it's not really Gamescom that's the problem. It's the fact that everything's a preview. And that's not even to mention the exclusivity deals around early access to games in production.