The Venator is why I fell in love with large-scale space battles as a kid, so I will try my best to be as objective as possible here.
The Venator has been extremely fun to build and play thus far. It is the first non-huge ship in the game to have squad 5! which is absolutely crazy. There are ways to build it to launch upwards of 8 squads in one activation, but I don't think it's anything more than a gimmick. Another excellent feature is the SPHA-T cannon upgrade which allows its side and front arcs to become ignition arcs.
So far, the way I see it is you can build it for 1 of 3 reasons:
1. You need a supercarrier for pushing an unholy amount of squads
2. You would like to use the SPHA-T cannons
3.You need a Reaccuring Fleet Command
If you aren't doing one of those things, I believe you're better off spending the points on a clam. That being said, the Venator can be used without these things, but if you got the points for SPHA-T, then I'd highly suggest it.
Another thing, the Venator I(Ven) is the less defensive of the two, and it shows. If the Ven I takes any amount of sustained fire, it will sink faster than most larges, so consider taking Lumi(com), Barris Offee, or maybe Adi Galla to boost the durability and make up for the absence of a Def Ret.