Yes, more enemies does not = better at all. It gets to the point of being annoying. Did anyone LIKE fighting off wolves, minotaurs, brown bears, black bears, mountain lions, etc. every 2 minutes along a road or even out the woods in Oblivion? Because I sure didn't. And I don't want to do the same in the water. The amount of slaughterfish they had in Oblivion was just fine, but adding a lot of passive fish would be a great thing. I wouldn't mind however their being one giant squid / octopus or some kind of sea serpent.
A specific example coming from Morrowind comes to mind
One thing with bethesda is that, as poignant, realistic immersive and story driven as their games can be they have this ideology that all monsters are evil and are going to attack you. . You may have those profound story line with lots of characters who manage to escape manichean characterisation whereas all the monsters are treated as dumb cannonfodder only there to help you level up and improve your skills... Beware the carnivorous seal and the evil nymph
( not to mention the wicked spriggan ) Olivion was the first game to introduce deers and neutral creatures so the quiet little brooks werent so bad after all... Anyway with flying creatures back in the elder scrolls look up and watch out.. the cliff racers might be back
It seems to me there were less baddies in the wild back in Daggerfall. Or is just my memory playing tricks on me? Or is it just that the world map was bigger?