I'm pretty sure the devs didn't just say, "Screw the lore, its gonna be a forest".
:lol: I'm pretty sure that's what they did!
Tons of games are set in forests. Not many are set in lush, verdant, exotic jungles - at least, games that don't have guns and involve smuggling and stuff.
But, as has already been mentioned in the thread, the jungle loss is symptomatic of other things that were 'lost' - a distinct Imperial culture to go along with the race, believable political systems and hierarchies, a sense of history to the game world, of a past - even a fictional past! - that is recognized and mentioned by the NPCs.
To me, there was a great feeling in the town/city layouts that these were not cities that were constructed hundreds of years ago, that had generations of inhabitants. Rather, they felt like they had been laid down not ten years ago.