Yeah, I feel using the Gorn in this way is the series' first big 'lore' mistake. Arena is famous (infamous) for the Gorn captain, and I get wanting to 'redeem' that, but they've gone so far beyond that. We're well past 'against canon', by the way. In Arena nobody even knew knew there was anyone else in the area beyond 'rumours and legends', and they'd never even heard the word 'Gorn' before. But none of that is integral to the episode, so it's not that a big deal if it's thrown out. But if they wanted these Xenomorph types, maybe they should have used something else. The Tzenkethi spring to mind, something that's been mentioned a few times on screen but never seen (they have been in both STO and the books, but very differently in each). Or just make up something new.
The episode itself, fine. Plot was a bit thin and basically 'Trek does Alien', but sometimes that's enough if the character stuff can hold it up, and it really does. I was going to give props for the best, but that would basically the the whole cast. Sad to see Hemmer go, he was an interesting take on the 'cranky' character type. I really hope his short tenure - he was in five episodes plus a brief shot in a sixth - was the actor's choice rather than something else. I wonder if we're going to get Scott as his replacement.