The Vigilance is not half-bad in a couple of niche roles;
- slap Safety Overrides, a Typhoon Reaper, and an HMG on it and it's a pretty decent suicide torpedo boat,
- slap an Ion Beam or HVD and a Sabot Pod into it and it's a good support ship,
- various boring Grav Beam/HVD and Harpoon/Breach fits that serve unremarkably in a frigate cloud.
I think it could probably use a different ship system, possibly Canister Flak or a similar PD substitute, but it's not a bad ship; just an ordinary one.
EDIT: Really, I think the ur-issue is that the progression curve of the game leaves you with almost no time running a large frigate cloud, which is where Vigilances are the most useful. And even then, a lot of other frigates are better picks simply because they can do what the Vigilance does *and* do other things. The Fleet Size By DP mod does help a bit with making 'wide' fleets of smaller, less high-end ships more viable, but not quite.
So, probably chalk this one up to needing a bunch of the issues around the ship fixed, too.