Every good scientist needs a control.
lol
The only real test for a hypothesis is reality. And I doubt that you'll find a lot of players out there who field an IN fleet consisting only of CL's.
IF you want a proper test use an Armaggedon list
as intended (meaning a list consisting mainly of CL's and BC's) an look how it performs against a regular navy fleet (meaning an emperor, Mars, a combination of Lunar/Gothic/Dominator, some dauntless' and some Cobras to fill up points). I'll doub't that the Armaggedon list will be on the winning side...
My 2 cents: If i get the designers intenion correctly the CL's should work as a kind of "half cruiser", so 2 CL's should do the work of 1 regular cruiser in another fleet. The probem is, that due to the mechanics (especially of shields) such a "half cruiser" is usually worse than 0.5 cruisers. Maybe not at 1 on 1 (or in this case 1 on 2

) but surly on the fleet level. so to bring them in line I see 3 options
a) forget about the whole "Half line cruiser" Idea an make them real light crusiers. meaning beef up speed/turns and make the weaponary more front-centred or better flexible (F/L/R)
b) improve their combat stats so that they can hold a line: 2nd shield will do the job, but 2/3of a regular Crusiers armament should also do it if you want to stay with 1 shield
c) decrease their price a good bit. At ~80-90 points I would consider to use some of them (but even than not more than say 3 ships on 1500 Point and only if the opponent isn't too competitive) but not at the current price.
From a historical view the whole concept is a bit weird: CL's were usually never more than oversized escorts (or refitted civil ships) and could never stand a chance against real ships of the Line.