Ship mix, and larger tactical considerations are being used now.
In the days of the CBG--Carrier Battle Group--the escort mix needed to be larger, since the ships were smaller, weapons-wise, individually. So, you needed more vessels to better balance the anti-air and ASW coverage. Back in the FF & FFG days, those vessels were almost only anti-aircraft oriented. Which was still good, as we had Forrest Sherman "gun" DDGs which combined ASW and anti-surface capabilities.
All of which pretty much necessitated including at least an AO to the CBG, just to keep it moving.
But, since the "fast" AO did not really work out, what became much easier was to just send the AO/AOE/AOF/AOR ahead to rendezvous with the CBG en route.
Similarly, after the California/Truxtun/Texas CGNs retired, and we went to the various Spru-Can escorts, things changed. You only needed a Tico CG to carry Aegis, and to be the battle coordination network hub. VLS really solved the magazine/launcher limitations, too.
Back in the days of having 5-6 (or more) escorts also meant that there was far more risk of the brown-shoes in the birdfarm running one of the "small boys" over as they played their aviating reindeer games.
And, the capabilities surface-to-air or surface-to-surface combat ought to be well covered by the air group--unless an alpha strike is called away, naturally.
As to ASW, well, there's a reason it's called Amazingly Slow Warfare. And, "slow" is not an aspect of flight ops, whether by CBG or by CSG. Your best bet there is to just not engage belligerents with a credible sub threat; and to use your elint/humint to put your subs on the other guy's subs before they get to your carriers.