I don't have any problems with the energy system. For one thing, it forces people to take a break from gaming. You can't blame DL if you didn't get something done, because you can do your stuff (homework, bills, etc) while waiting for energy.

I do like the long timers. It took me about a month to get from level 1 to 21 and unlock all the campaigns. Without the timers and with unlimited energy, I would be done it in a couple of days.

The other alternative is to give tiny amounts of experience, and expect you to grind 24/7. Do you really want that?