Ugh...jungle. That would be a unpleasant slog and the helicopters would have a hard time getting those great aerial shots with all the excess foliage. I've often wondered why Namibia/Botswana/South Africa haven't been considered. All three countries have amazing terrain of the un-soggy kind and reasonably stable political situations.
I think the S. American venues are great too, but would want to stay away from the jungly bits - I've seen some of those Amazonian roads in the wet (and SE Asia as well) and it would be just wrong for this race IMHO. Its the desert open landscapes that rivet my attention as much as the teams.