Some Sort of Map Briefing

I admit that this suggestion is a bit vague but y'all should be able to catch my drift. I'm more identifying a problem than suggesting anything.

As great as custom units are, it's impossible to know how far a custom map's units are going to be from the normal base units. So when a person begins a custom map for the first time, he has no idea what to expect or how to prepare. (For eg: will there be super powerful defensive units?)

This problem was already present with scenarios (eg: does this scenario contain air units/marines), but I believe the problem will be exacerbated with custom maps. Also, relying on the person who is hosting the game to give you such information isn't really a solution.

I will publish a short summary of all units, specials e.g., in the forum when releasing my scenario.

otherwise learning by doing

Learning by doing is a good thing. But nevertheless there should be at least some info what awaits you on that custom map.

There could be something like a mini showcase of some units and its specialties in the game lobby that are not shown in the in game unit tab.
The map creator could be free to add that like the map or scenario description.

There is a unit tap, you click it and then you see everything >:D

You can see all the basic values ofc. But you cant see if a specific unit is able to take a city or is transportable for example.

Acqui is talking about before the game starts I think.

Perhaps we could show this kind of information on the website if we'll ever make a separate page for each map. Something like the current units page on the website, just for each map.