Being a small company there would only be a few programers working on it so development is slow and 1C might only be giving support to games that have alot of interest shown in them. Unfortunatly the demographics for this game is 4x4 and off-road enthusiasts. Of couse that would change if editing tools were to be released so we are stuck like a truck in the mud
As for editing the game ourselves goes I don't know much about udk and its anti-piracy software like securom and such, but if udk is anything like sdk you could open and customize the demo in the udk editor if the demo has no security lock.