...weapon placement is a legacy feature, and allowing vehicle placement is the worst possible thing that could happen to the map editor.
Clearly this sounds a little unreasonable, so I will elaborate. I haven't played on any maps that make good use of vehicles in far cry. EVER. A vehicle becomes a prop used by unimaginative map makers and produces some of the most unimpressive, boring maps out there. It spawns countless 'two base' maps, maps with two many open spaces, no attention to detail and truly awful gameplay flow.
Not including vehicles in the map maker drives the quality of user maps up, because people are forced to design good gameplay spaces, not just a map tht has the coolest vehicle in the game and not a lot else. This means that the average user map will be better, and we wont get stuck playing on maps with an imagined gameplay flow that does not actually work ('wouldent it be cool if people attacked the fort in cars and drove away'). Of course this is only my personal opinion, but I just thoght it was important for people to see that there is another side to the whole 'no vehicle' situation.
And on the subject of weapon placement, if you cant design a multiplayer map for all the weapons in the game, that is naturally balanced by design, well......