Probably some hyper specialised thing that causes massive arguments whenever it is brought up.
A true battlecruiser carrier, probably. Something fast...
This wretched thing from aeons ago - the engines of a Conquest with "stuff" bolted to the front of it.
Okay number of missiles for support, but none of them face directly forwards.
Respectable number of big guns, but most of them are fixed. On a capital.
The only one of these that isn't fixed is energy, but that's also the only arc that can potentially 100% cover the front with PD. Do you put a Paladin in there or more gun? Who knows, have an argument to find out!
Is there a point to any carrier when Heron exists?
Heron has destroyer level PPT and has to spend a significant amount of it's very limited OP mitigating this (and it already can't really afford weapons), otherwise it can't handle fleet actions that well and frequently has to go home early.
So yes, there are reasons you might want to use other carriers.