I would be trying to think about how the Gorn see themselves. I don’t think it should be too evocative of a lizard. It shouldn’t be obvious, but as you suggest something that has the right connotations.That’s an interesting thought exercise. I have the feeling that the since the TOS Gorn were big, slow lizards, their ship design would have probably followed suit. Something simple, yet brutal.
Look how the original Klingon D7 doesn’t really gel with what they did with Klingon ships later. The D7 has a grace to it’s design even as it also looks ghostly or wraith like. It has an animalistic quality to it while not looking like an animal. Later Klingon ships were dark, heavy, clanky and austere looking as they redefined the Klingons. After the D7 and K’Tinga their ships were no longer, well, beautiful to look at. They now look like heavy machinery.
The only thing avian like about the TOS Romulan BoP is the upswept pylons accentuated by the bird-of-prey graphic. Otherwise the BoP looks rather manta ray like with a suggestion of submarine to it. As I said upthread the Romulan BoP has a pulp sci-fi look to it largely because of that tailfin which serves no obvious function other than appearance.