It's an MMO. There is no "End" as with a single player game that has a set campaign.
Is there enough to do at the higher levels? I'm not sure as I'm only in the early 60s. I'm not sure what the endgame level range is. But it's your basic city builder/ pvp brower game based on timers. Hideously slow timers in some case. Down right draconian timers in other cases.
It's purpose is to make the development company money of course. For us, it provides a Greco centric playground of sort. That's Ancient Greek Centric, not the current economical meltdown simulator model we have today. It also has some Roman and Carthogenian units so when exactly this is I'm not sure. Game Devs never cared much for being true or accurate to History, so best guess is maybe 200 BCE.
How does it compare to WoW? Well first off, this is a BROWSER GAME. WoW is a fully fleshed out interactive video game with heavy Role Playing elements. This is a point and click adventure with timer watching, a little more clicking, and lots of waiting with claims at being a strategy game. It is no where as interactive or vast as WoW but it's not trying to be. WoW is an entirely separate animal. You're asking for a comparison between a painted turtle and a silverback gorilla.
Okay to be fair there are light strategic elements to the game but given that most things move at glacial speeds, you have plenty of time to consider your options, take a nap, have a shower, go for a walk, and then come back and actually make your decision on something.