DS9 is small??? Its 1 mile wide!! I don't think that's small by anyone's standard.
In comparison to B5 ships, ST ships seem a lot more advanced. Earth ships in particular are lumbering giants with little bang for the buck. A Galaxy class ship seems packed with high tech equipment in a smaller space, with artifical gravity and advanced features.
I'm as big of a fan of DS9 as one can be... but I also know my Babylon 5. And you're quite wrong.
1) DS9 is tiny, tiny, tiny compared to Babylon 5, and even many other stations in the Trek universe. Sure it has a decent circumference, but its structure is very thin. Think branches on a tree limb; Just because the limb is long and full doesn't mean you can make a table out of it.
2) Babylon 5 was much more realistic as far as offensive/defensive capability. At first glance, Earth ships in Babylon 5 seem cumbersome compared to Starfleet vessels. But that's only because they lack toys like shields
(which I still think are a silly concept) and artificial gravity, which in all likelihood will be one of the final things we master as far as space travel.
In Babylon 5, Earth is extremely militaristic. And the areas of advancement in starship technology reflect that.
An Earth Alliance Omega Class, while seemingly inferior to something as glamourous as a Galaxy Class from Starfleet, packs *significantly* more firepower and armor.
As I said, on the whole it's very difficult to compare Earth Alliance ships to Starfleet ships. But when comparing battle capability specifically, there's no contest; Earth Alliance by a mile.