Boats

[Hussar]

Not an entirely new topic, but I'd like to suggest boats.  In many parts of the world, land travel was difficult, especially with cargo, so the highways were rivers rather than roads, and watercraft were extremely important.

Boats would also be used for fishing (another thing I'd like to see).

At an early stage, we could build dugout canoes or birch bark canoes.  Later, perhaps boats or barges made of lumber.  Watercraft could have intrinsic storage capacity (less for canoes, much more for barges).  We could use the CarryCapacity mod or similar feature to portage canoes from one river to the next.  We could dig canals for barges

World generation would need to provide navigable rivers and creeks. I'd like to see deeper rivers and lakes, with some shallow fords and swamps.  If swimming were more difficult, fords, ferries, and bridges would be more important. 

[ruggbean]

I'd like to second this. While it is easy to pick off things that are swimming in the water, like drifters or wolves, if want to go from point A to point B quickly, boats would be the most ideal method of transport.

[Feone Varen]

This would be great, having rivers as efficient transport options makes a lot of sense in terms of realism as well. Much further in the future it would be awesome if we were able to build ships out of blocks too (at least if water features become larger and more connected).

Some of the most fun I've had in Terrafirmacraft was with another mod that added boats like that (this one iirc) Being able to travel the oceans and visit far away places with animals, storage capacity and some infrastructure (the bits and pieces that didn't cause world corruption ) is awesome.