Fighting with capital can be a lot of fun, you need to plan where you will be, you need to selectively activate your weapon, you need to decide when to put shield on or off. If you can multitask you can even engage 2 target at the same time. For me frigate are pretty boring, as there's not much to do: find an angle, go in, go out, vent and repeat.
There's no way to keep the game balanced and to make a single frigate influence the battle as much as a capital anyway. You can get 6-8 frigates for the battle point cost of an onslaught.
Investing in combat stats have some really good boost that influence frigate (the flat armor and percentage based speed boost are probly better on frigate actually). On some fight I'd deploy mostly capitals and cruiser and personally pilot a frigate/destroyer to hunt early enemy frigates, then I'd order it to retreat and switch to the bigger target.
As I've said before, pretty much all of the leadership skills can be skipped, or kept at 1. Industry skills can be skipped entirely. This allow you to max a lot of combat and technology skills.
Spend 3 points to get 6 officers, +!0% speed bonus on all ship,
Spend 6 point to max combat and technology
Spend 7 point to get loadout design, electronic warfare 1 and sustained burn+5
That leaves you with 27 points to spend in combat and technology as you want. This is 9 maxed skills, compared to the seven your officers get. For 6 point you can get the lvl 3 fleetwide fighter skills and 2 more officers, leaving you with 7 maxed "combat skills" just as an officer.
Now why would you try to get more combat skills than an officer rather than going for fleetwide skills? Because you can pilot your ship a lot better, you are where you are needed when you are needed. You can solo gigantic fleet with only a Paragon, an Aurora and some support cruiser/carrier. You don't need the additional CR because you can plow through the enemy, retreat and clean the riff raff with fast ship in big engagement. Honestly, CR is only a problem in the early game, when you don't have much ship and in the endgame when you fight fleet that are several time the size of your own. And the latter can be ignored if you cycle your ships.
The real problem is industry skills, they are generally very useless unless maxed, and even then are mostly equivalent to having more money.