The balancing problem was weighed versus Cost effectiveness versus other units of the same tech. And most Light Carrier spams come early in the game before research on a phase jump inhibitor is completed. Combined with the near instant build rate of SC from earlier versions, Light Carriers were grossly overpowered and have since been reduced to a more balanced state.
Light Carriers are still very powerful in Entrench Beta 3 and are often the prefered mode of destruction for fully upgraded starbases (Which now seem extra powerful from previous versions which is cool, finally they feel right) This is obviously a post by a Light Carrier spammer suggesting "Counters" Without any process of logical thinking involved Here are some holes from previous versions in your counters
*Kol Battleship/Halcyon Carrier counter. 3000 Credits 450Metal 250Crystal and not including the EXTRA research to deploy suffcient numbers. Also you must invest in levels because a level 1 flak burst is going to do not a damn thing, so there's 1250-2750 more credits. THEN if you're actually a light carrier spammer, you're going to have enough bombers to destroy any cap ship in one pass, rendering them utterly worthless.
*Flak Frigates. Pretty useless. More for mopping up what the Kol hasn't killed. The Range increase in version B3 was a good boost, though by no means the end all solution.
*Phase Jump Inhibitor. Aside from taking quite a while to research (Not including other more important researches like autocannon or beam upgrades) the Phase Jump Inhibitor has about the armor as the average 1lb block of tofu. So during a Light Carrier raid, chances are this will be one of the first things to go (Probably in a quater of one pass)
The biggest problem is Anti Strike craft is too specialized (Relegated to 1 frigate and 1 capital ship ability throughtout each faction. Some Generalzed counters would be nice, at least for every capital ship to have some basic anti-Strike weapons. Particularly for the Supporting Battlecruisers (Akkan/Rapture/Marauder).
Myself, and I think (or hope) everyone isn't asking for a brick wall for strike craft. If you throw 200 Light Carriers into the battle, it should be able to mop the floor with everything of lesser size, but against a similarly sized fleet, it should still be a toss up (Depending on composition and balance/specialization). That's what makes balancing this game so atrociously difficult I think, because unlike shallow RTS games like RA3 where each unit has an end all counter, Sins is about balancing support-damage instead.