But I thought this thread was about ships? How about specialist amphibious shipping that would make landings easier?
I've always had an idea about this that I have seen others share as well, that I think resolves the problem with landings very easily.
First off, all transport ships are able to make opposed and unapposed landings, for gameplay and historic reasons. If you ever look at some of the pictures from the Gallipoli campaign in WW1 you can see some great shots of transports with huge wooden walkways/ramps to allow infantry to disembark onto the beaches.
But if using just regular transports, then the units making the landing suffer the full amphibious landing penalties, because its a very innefecient and vulnerable way to land troops: its hard to imagine D-Day working without the Higgins boats because the German artillery could have decimated those vulnerable transports as they moved in to the beaches. So if you make an opposed landing without dedicated landing craft you get big penalties: if the enemy has costal fortifications, then the costal fort bonus should be doubled to emphasis the need for dedicated landing craft to deal with dug in infantry.
Secondly, there should be a side tech off of marines should be "Amphibious Landing Craft", with at least 2 techs for it. The first tech would unlock an attachable "Brigade" for transports (not an automatic upgrade) which would increase their cost by a few ICs to represent building all those Higgins boats.
If, say, landing craft reduced the amphibious landing penalty by half (50%), then it would work similiar to as follows:
- Infantry, Mountain, Marines, Para brigades would get the full 50% reduction. Marines already get other reductions in amphibious landings, so no need to make their LCVPs (Landing Craft, Vehicle, Personnel or Higgins boat) more effective for some reason.

- Motorized brigades would get a 45% reduction because they are just like regular infantry, but have trucks to increase their speed: this would represent them landing on the beaches without trucks like normal infantry, hence the lesser yet similiar reduction.
- Mechanized brigades would get a 5% reduction in the penalty for most of the same reasons as above, except that mechanized infantry invests alot into its half-tracks, etc. and wouldn't be able to bring those along.
- Armoured brigades would get a 2% reduction to represent the first steps towards amphibious tanks and the like, but they should normally already have larger penalties than the other types.
After that, the next tech level would represent larger and more advanced landing craft, like LCTs (Landing Craft, Tank) and LCMs (Landing Craft, Mechanized) that would increase the reduction for all types as it would allow greater numbers to reach the beaches, more supplies, etc. and would reduce the penalty for landing by, say 79% (I'm just making up these %s to show the general idea, not the specifics of what division gets exactly what reduction).
- Infantry, Mountain, Marines, Para brigades would get the full 70% reduction.
- Motorized brigades would get a 65% reduction for the same reasons as above.
- Mechanized brigades would get a 40% reduction in the penalty for the same reasons as above, but in this case they can now land with some of their APCs on the larger craft. They still should not be the units best suited for invading a defended beach, however.
- Armoured brigades would get a 15% reduction to represent the newer craft able to carry tanks to the beaches, but tanks being landed are still vulnerable to the dug in defenders (wet terrain, not able to move fast, not open country, etc.).
Then there should probably be a third tech for more modern landing craft and landing technology, although this is debatable and not really necissary the Allies used their craft for many years: the US used LCTs in Korea and Vietnam, for example, and reducing the negative modifer any further could make landings too easy: in fact, I am tempted to go back and reduce the reductions, but feel that the exact number isn't important, but the concept I want to get accross.
One other thing I would like to see in the game would be for an 'Amphibious Vehicle ' tech that could be abother off shoot of marines, or a mix of marines and motorized that would represent vehicles such as the DUKW, Schwimmwagen, etc. that could give a small modifier to Infantry, marine, mechanized and motorized troops when attempting amphibious landings and when attempting to fight accross rivers. It would be small (5% or so) and could be followed by a 'Amphibious Tank' tech that would give armoured brigades that (5%) bonus as well.