..... omg.... business idea! running around planets being paid to restore sections of land to their original appearance
regenerative land couldn't work, seems like it might be more of a nuisance than anything useful... imagine building a mining outpost on a planet, get a new game and go inactive for a month... come back online and the mine shaft has been filled in.... meaning you'd have to dig it back out to finish mining
given how massive planets are, I don't see the starting planet running out of fuel within the lifespan of the game.....
however a compromise could be made.... If the area around the ARK ship were to be restricted to players under a certain level, or if it was a "once you leave you can't come back" thing, The planet could be regenerative (meaning ores and dirt regenerate)..... to prevent overpopulation this area could destroy buildings when players leave the protected area (either after they reach their level, or just when they leave depending which scenario is used)....
this would guarantee players somewhere with the basic resources needed to get started in life, and prevent players coming back to take advantage of the regenerative ores (1 mining outpost, harvesting fuel from an infinite ore vein?..... talk about an imbalanced market xD)
with response to things looking ugly after a while... I concur.... if you've ever played on a minecraft map that doesn't reset every 3 months, you'll know that even infinite worlds look hideous after a few months of mining......
Dual Universe would have the problem these minecraft servers have.... which is players get bored of looking for somewhere to set up and get started because they'd have to travel for hours to find some undisturbed land