The thing is, if you had a CVE/Surface Action Group that could do inshore bombardment, would you not still have the same problem with puffy ack? A cruiser/destroyer group would still have 5 inchers that could do the same thing that our current TG's do. So the question becomes how do you create a shore bombardment group that doesn't have the capability to ack the base?
You could keep the cruisers with the big CV's and only let them use 8 inchers on target, or if you want to go the CVE route, force the DD's to choose between AP, HE, and AA rounds, and limit the reach of AA fire.
Just thinking out loud,
-Muzzy