The idea sounds good. It would be cool if you could chose what time period you can start in. Each one would influnece you character's fighting style, weapon, and type of magic. Like being in 650000000 B.C, youo could not use magic but you do alot of damage and have alot of HP. Portals between epochs would be guarded by High level monsters, in order to keep newbies out of danger. Then there would be a Player vs player area in a "battle epoch", like an end of time place where you choose a PvP battleground. Maybe put a colisuem in the game to get rare items and weapons.
Also concerning epoch stats-
65000000 B.C- alot of strength and hp, no magic.
12000 B.C- Magic users, but little to no melee attackers.
600 A.D- Contains knights and little magic users, some use technology
1000 A.D- Perfect balance between Strength, Magic, and technology.
3200 A.D.- Little magic or strength, rely on technology. Also Robots
.
If your confused strength is amount of HP and damage. Magic users are.... pretty self explanitory. Technology is using guns, crossbows ect.
The last place in the game to go to is the end of time, it is guarded by the mightest of ceatures, at the end you get upgraded powers from Spekkio. Then the choice to fight Lavos.