To answer the Dragon SP question you could simply add the flora (plants) to the scripts in Dragon SP, its is very simple to do if you follow the examples and key at the top of the scripts.
The map sizes are different for each map, that is why Dragon has trouble with each one. You take which ever map you desire and copy/paste into map0 then edit as desired till done then place it back in the proper map with UOCopy, so far this is the only real way to do it all in Dragon.
You can also take which ever world you come up with on map0 and cut them out and paste into any map you like. It works the same in either directions.
Ocean vs Water, in Dragon 9+plus you used the same color for both water and ocean but this created transition problems along the coast some times on the North and West sides (chunky looking blocks).
In version 11 it was split into 2 seperate terrains much like it is done in the real UO. Oceans are done up to around a screens width of the coast line and then they are painted with the water -5 which tells the scripts to create the proper shore line that looks much smoother but has limited elevations.
Hope that covered it all, if not just ask for clarification. If I screwed something up I'm sure someone will let me know as well.
Dev