Drizzt are you sure your native language is English? Reading your posts is like trying to dig a hole with a spoon.
Anyway, to contribute to the discussion, I would say look at Might and Magic VI: The Mandate of Heaven for an example of MMO elements in a single player RPG game. It doesn't nab
all of the elements precisely, but it does a damn good job of getting there. There are three main classes and then three classes that are crossovers of the three main ones. You have Knight, Cleric, and Sorceror for your main classes. The Knight can't use magic but is easily the toughest class in the game. With the Body Building skill (in this game skills are like specializations and traits you can learn; body building directly adds HP to your total each level up) a Knight can surpass every other class in hit points and as such last the longest in fights. This makes the Knight your "tank" class. Magic in this game is extremely useful, however, so taking a Knight may not be viable until late-game, but we'll get to that later.
The second class is Cleric, and as you can probably already guess, this is your "healer" class. In Might and Magic, there are two schools of magic; Clerical and Elemental. Clerical magic is then divided into the three "elements" of Spirit, Mind, and Body. Spirit focuses on buffs and cures, Mind focuses on dealing damage and confusing enemies, and Body focuses on healing and recovery. However, each element has at least one spell that goes out of their focus. For example Body has a spell that deals Physical damage to an enemy, and Spirit has a minor heal. These spells aren't as powerful as their focused counterparts, but gives that sort of multi-purpose feel to it. I'll talk about Elemental magic when I get to the Sorceror. As could be expected, the Cleric can use Clerical magic and as such does more healing, buffing, and support than attacking, but since Clerics in this game can wear chainmail armor at later levels as well as use shields, they make effective "off tanks" as well, if for some reason your tank dies. But as it were you'll want to build your Cleric as a healer; learning the Meditation skill (the mana equivalent of body building), giving him points in Personality (charisma for you D&Ders), equipping gear that increases healing effects, etc. Clerics have the greatest healing potential, but can also deal a fair amount of damage with the advanced disciplines of Light and Dark magic.
Third, is the Sorceror. He's your basic "glass cannon" mage type, with low HP and defense but massive damage potential through his spells (and if you steadily increase his skill in daggers then you can eventually inflict triple damage on attack). He uses the Elemental magic, which is split into the four classical elements of Fire, Air, Water, and Earth. Fire is, as expected, about dealing heavy damage to single and multiple targets. Air is about flight, movement, and speed. Water is about changing properties, travel, and a lesser form of damage. Water has a spell that lets you enchant armor, weapons, and certain items with a random magical property, and also spells that let you walk on water, teleport to major cities you've been to before, and even set your own warp points to recall back to at a later time. Most of Water magic's damage comes in the form of ice, but damage isn't it's main focus. Earth is about defense, protection, and toughness. All elemental schools also have aspects of other schools as well. Fire has a Haste spell, Air has a lightning storm spell, Water has water walking, Earth has Turn to Stone (and its curative form Stone to Flesh). Sorcerors have the most versatility in regards to magic, and can even learn some healing spells with the advanced disciplines of Light and Dark magic. However, they are puny and deal little physical damage while at the same time being as fragile as a stick. But with their incredible capacity for mana growth, they'll make sure to take down a few enemies before going down themselves.
Now, I mentioned that there were three more classes that are like crossovers of the three main classes. These are Paladin, Archer, and Druid. The Paladin is a mix of Knight and Cleric, and as such can be as effective (if not more effective due to healing spells) a tank as a Knight. However, with the combination, the two classes' "powers" are diluted and won't be as strong as the individual classes themselves. A Paladin doesn't have the potential for massive amounts of hp like the Knight has, and will also miss out on Light and Dark magic (that only Clerics and Sorcerors can learn). They can still learn every school of Clerical magic, but unless you focus on building up those schools (and thus taking away from his potential as a tank) then he won't be as powerful as a Cleric. Something to note is that Paladins start the game already knowing Spirit magic, while Clerics innately know Body magic.
The Archer is a mix of Knight and Sorceror, and is the only class who starts the game with the Bow skill (everyone else has to learn it, but the Knight can select it as one of his two "bonus" skills at the start of the game). Like the Sorceror, the Archer can use Elemental magic, and is relatively powerful early game (bows are OP). The Archer inherits the Knight's damage capability (to a lesser extent), but also inherits the Sorceror's frailty. It's not as pronounced as a Sorceror because of the Knight part of the mix, but an Archer is definitely less sturdy than a Knight or Paladin (or in some cases even a Cleric). Archers will start the game knowing Air magic, while Sorcerors begin with Fire.
Finally, there's the Druid. I don't have much personal experience with Druids because I mainly stick to one of the "default" party makeups of Paladin/Archer/Cleric/Sorceror or Knight/Paladin/Cleric/Sorceror, but I'll try my best. Druids are a mix of Cleric and Sorceror and as such are physically weak (only the sorceror deals less physical damage than a druid). The trade-off for this is that Druids can access all schools of magic except Light and Dark. So in effect, Druids are like Red Mages from Final Fantasy. Druids are the most versatile in regards to magic, but as stated they are horrible fighters. Their strength lies in their versatility, and if you're having trouble deciding between one of the other hybrid classes then this one is usually a good choice because it takes the important parts of the other hybrids (the magic) and puts them together. It's up to you to decide whether having another weakling in your party is worth the extra magic potential.
At character creation, you have to make a party of four characters. Having at least two healers is nearly a must in this game, as a lot of times your non-tank characters will either get knocked out or disabled in some way, or have status effects put on them that forces them to expend their mana curing these statuses instead of healing. It creates a good amount of tension, actually, because you have to think on your feet as to how to keep your party alive as well as healthy (free of statuses). Sometimes you just have to make a sacrifice and not cure statuses for the sake of healing. As long and ranting as this post is, I think it sums up the game fairly well, and displays the "MMO" elements it uses to a good degree. This game is also similar to MMOs in that your party is just a group of adventurers with no real "plot significance" (other than being the main party), and as such the developers were able to allow flexibility in party creation. It's by no means exactly what you're looking for, but this is certainly a huge step in the right direction (and it came out in the 90s, fancy that).
SO, that said, here's a link to a Might and Magic inspired RPG Maker game:
http://www.legendoferthia.com/