Eve Online/ Dust 514 is a modern example of a totally destructible item environment. It works pretty well. Only problem is it's skill system and combat system. (btw... Russians love it...) My only deal with it is that it takes FOREVER to be useful. They have a real time skill system to pilot any ship. For some ships like, say, an asteroid mining barge you can fly competently in about a month. Huge "deathstar" type Titans, years. There is a huge divide between veterans and noobies. If you can not fly T2 ships, battleship or above, there is much you can not do. Unlike the ship to ship combat system of Star Trek Online, Eve is just orbiting at your weapons optimal orbit and trajectory and whoever has the highest skill or best weapons wins. There is no strategic targeting of guns or shield generators, etc.
BUT... Eve has one of the most dynamic economies, politics, and just deepness because of it's sandbox. Seriously, they write academic papers on Eve.
But, as sandboxy as it is, Eve does not go far enough. You still do not have total interaction with planets. You can not just fly by with a Titan to a planet with Dust marines and alter tides while nuking entire portions of continents. (They say they are working on that, though). You can not do space walks. They have an avatar, but for the most part, your Avatar is a spaceship. I can not strap on guns and park a ship in a station and be a gambler in a space cantina. Nor can I be both a marine and a fighter pilot. Shame too. They paid those kids at White Wolf a lot of money for a state of the art Avatar system to walk in stations and do stuff just like that. Only thing is many of the playerbase play Eve like a 4x and have multiple clients of star ships. The beautiful walking Avatars interfered with managing fleets of 2 to 6 ships and did not interest the players. they had to abandon it to where the only thing you can do on foot is hang in a captain's quarter.
Using these statements from you, I am in agreeance, and it furthers why I think there should be a scrapping of the level system.
Levels divide players and in a sense are unrealistic, as if you are better at something in real life through experience you get more knowledge on it and can operate faster: And people can naturally represent this by being better at the game.
With removal of level requirements the only thing that would truly separate people is in game wealth, and with an RPG that can be abridged with both expensive costs of more advanced equipment and the fact that if a bunch of newer folks band together to take on a more advanced player and ambush him, or scavenge after a battle between the more advanced players they can cash the rewards. And with a post apocalyptic environment you play as an individual: An individual who can fight and do other stuff.
As for Russians loving it, I am fully aware. My daughter's husbands have played Eve online and I see advertisement on television for it more then a few times

As for me though it removes tactical and intimate feelings of personal interaction for me. It's too much of a massive strategy game and while I like strategy, if you just have a mathematical calculus time waster I am not buying it. It's why I am not a big fan of games like Europa Universalis. Alpha Centauri doesn't fall into that trap because 1. It has interaction and great depth of story to it and 2. It has tactics and intimate battles. They may not be the most detailed things on the planet but they are there and the action is there. And even the micromanagement level of building bases and cities is there where you can customize and tool your cities for specific jobs and purposes. It may not be as intimate in tactics or micromanagement as say games like Age of Empires 2, but it's a nice balance of tactics and strategy.
A game that I tried was Fallen Earth, and it would've been extremely good if it wasn't for the abhorrid level system and gap. It had resource collection and looting, and even people making factions with distinct cultures but it took too long to be of any use to anyone due to the incredibly tedious and slow level systems.
The system I dream of is simply this:
If any of you have played the old Fallout games, imagine you have a two point system: You have your base attributes,
Strength,
Perception,
Endurance,
Charisma,
Intelligence,
Agility,
Luck.
You have a certain amount of points that you are automatically given, at the creation process to make your character with. Everyone gets the same amount of points and time and exploits aren't going to change this base. Each base affects a multitude of different skills or just things about your character. How this translates?
Strength would be good for anything that involves strength. Handling heavier weapons, melee, or raw labour, and generally makes your physical attacks have more damage. It can also be tied with endurance for carrying weights/gear, can also help with lockpicking.
Perception would be good for anything involved ranged weapons, it would give you better alertness (there could be a identification system like a HUD interface and players with higher perception identify things from a longer distance) and makes you more accurate with firearms, or lockpicking.
Endurance would make you physically tougher and more resilient, and may tie in with certain skills or enhance them, such as chem making as you can endure things better. It can also be tied to strength for carrying limits, or tied with Agility to determine how long you can sprint.
Charisma affects your base interactions with NPC's, it may give more chat options and it also can help with taming animals or what not. A skill for NPC interaction mainly, and maybe the higher you have it you can do certain actions as well that people with lower Charisma can't.
Intelligence would be mainly for certain skills, like hacking, medical/healing skills and also fixing or creating gear, among other things. People with higher or lower intelligence may also have interesting chat options, the former having very intelligent, approaching genius knowledge in NPC conversations and the other being that of a mental deficient. And both can have their advantages even. (the latter may have people giving sympathy to you.)
Agility would be for things just like general movement speed, skills like pickpocketing, how fast you can sprint and tied with other skills like melee and sneaking.
Luck would translate to how often someone gets a critical hit, chances of finding good loot in random generated containers and generally how well they are in gambling games. This would give a small boost in the latter as we don't want to unbalance any poker games happening inside the game

Then the second tier of points would have more points then the first, much more. These are for actual skills and they also go from ratio's of 1-10. 1 being the lowest and 10 being the highest, so if you are +7 in a skill you are pretty proficient at it and the higher you go the better you are at it, and thus the faster you do something/better. As for what skills are actually there that would have to be determined by someone actually making said online RPG.
My point is that with this sort of system, no gained levels whatsoever, with degrading items, can both be easily made and greatly improve gameplay. Throw in 4x Sandbox elements in there and you got a utopian game.