Full-foot fins worn with booties:
and here's a diver who prefers using traditional full-foot fins when he does his underwater photography:
My favourite kit - Pete Atkinson - Divernet
Let's get away from the simplistic notion of tropical waters=full-foot fins, cold waters=open-heel fins. The central issue isn't the fins, it's the footwear worn with the fins. Neoprene socks and thin-soled boots
can be worn with full-foot fins if their foot pockets are spacious enough. It would be better to focus on the fact that some footwear is so thick and bulky that it's going to be hard to find spacious enough foot pockets on full-foot fins.
As for wearing a drysuit with full-foot fins, I actually do just that when I snorkel in the North Sea. My old-fashioned drysuit comes with thin socks that fit very comfortably into my full-foots. When the Unisuit drysuit came out in the mid-1960s, Cressi marketed special full-foots with huge foot pockets to accommodate the bulky boots:
Finally, if you ever get the chance, have a look at a pair of full-foot Apollo Bio splits. The walls of the foot pocket are much thicker than normal and the design is intended to be worn by divers over footwear and not barefoot.
Make up your own mind about what kind of fins you want, whether full-foot or open-heel. As I said in my original post, the current diving culture in the West is in favour of open-heels. It wasn't always that way. If you want to bow to the majority view and opt for open-heels, fine. I shall continue to snorkel in the North Sea in my full-foots nevertheless!