movement enhancing troops

I would love to see a transport unit, that speeds up embarked units or helps them disembark faster if that doesn't break the game.

Similarly a transport on land that could speed up artillery or units in enemy lands. I talked in a previous thread about a medic tent that would increase the amount of wounded (part of the thread, not the game as of today) that also could lower the morale damage taken when an army is in a newly annexed province with low morale.

bicycle corps would be fun

exactly. More units ((:
or more roles for units to fill i guess.