Most of modern MMO games have traditional class system. That means you have to choose the class of your character in the very beginning of the game – when you create him. You have to make a very important choice because most games do not allow changing the class during the game. This choice is important because the class sets a lot of restrictions for your future gameplay. If you chose a warrior class in WoW you will never be able to cast spells and use magical staffs. Warrior class has a lot of restriction that do not allow you to become combat mage or rogue. If you have chosen the class you will have to play it until you give up the game.
On the one hand it is good, because it slows to avoid chaos. On the other hand it is mot great because any restrictions affect the gameplay. Elder Scrolls Online brings a new class system that differs from the traditional one. I was really surprised when I read this: http://elderscrollsonline.info/classes In ESO you also have to chose a class in the beginning of the game. But the class does not restrict your future experience.
When you pick up a class for your character in Elder Scrolls Online you receive 3 trees of class abilities. But the game offers you a lot of other ability trees. For example each type of weapon has its own tree and everyone can master the spells regardless the class. There are many additional spells you can master.
Any class can use any armor type and any weapon. That means you can become a mage with a sword and shield. You can be a Templar with a bow or a wizard with two swords. You can chose any role for yourself and your class does not affect your choice. For example if you chose a Templar class you can become a tank, damage dealer or spell caster. Everything depends on what combination of class skills, weapon and armor abilities you chose. On my opinion that is a very good experience.
Such flexible system allows you to change your specialization during the game. Lets say you started to play ESO as a Dragon Knight and started to learn skills for dealing damage, but after several days of gameplay you decide to become a tank. In Elder Scrolls online it is really possible. You don’t have to create new character – just take a shield and start to invest skill points into the tree you wish to master. That’s easy!