Simple premise really....add a ship to the fleet...an AKA or LST, something capable of marginally defending itself with single 5" guns, 40mm twin, etc. So long as that ship is up, the fleet is capable of landing tanks.
From that ship, player can spawn LVTS like usual, or take a tank in from the same LVT spawn points in an LCM.
While in the water, the player controls the LCM and whatever weaponry was carried based on the version.
Once the LCM makes shore, player switches to his pre-chosen GV, and the LCM magically goes poof.
Personally, I wouldn't mind seeing an amphibious fleet developed in conjunction with the standard fast CV fleet.
It would involve (obviously) developing some new ships, AKA, LST, maybe even a DE (provided the advantage is getting it much closer to shore), and why not...maybe a CVE with a limited array of aircraft (historically the US flew F4Fs and FMs, TBFs, and the Brits flew TBFs, Seafires and Sea Hurricanes from them). They would depend on the CV group for shore bombardment and air support, making them sitting ducks otherwise....
+2