One of the biggest difficulties in SL, is exploring using a vehicle with a fuel system. Lot of individuals - Myself included - use vehicles with the fuel system enabled, and at some point...we're going to need fuel, and gas stations are sadly far and few between, especially in Bellisseria, where it's strictly residential.
Having the ability to refuel our vehicle - be it aircraft, helicopter, car/truck or even boat - would I feel greatly increase the chances of people wanting to RP, travel and explore mainland SL.