I have played World in Flames on a wall. (we just used the maps from the box, unmodified counters, and a whole lot of poster putty, worked OK, but this was in 5th edition with a lower counter density than Super Deluxe, and a lot of the world still at "Asian" scale rather than the all-European scale on the MWiF maps.
one thing you need is to have the main areas of land conflict (northern Europe, China) at eye level or just below. the result of this is that a full map of Africa won't fit on the wall, directly below Europe. there are a few other such implications around the world.
so to realistically do it, you have to figure out what to do with all the mapped areas that are unlikely to see any counters at all, and when they are, will only be units in transit, well behind any combat front line.
which will lead you to using some sort of "off-map" boxes or pools or something, as on the edges of the World in Flames paper maps. It wouldn't be all that hard to home-brew up a solution for these realities.
I would get some experience playing the game well before one mounts the map of South America on a wall.