Also, there are apparently foods made with cooking that can offer exp boosts as well. I wouldn't be surprised if there were similar buffs for Karma and crafting from other foods.
But more importantly, leveling isn't that hard in the game that anyone should feel obligated to pay more to level faster. There will likely be people at the level cap by the end of the first week. Sure, someone will be the first person to hit that cap, and he might do so using exp boosts, but who cares? The people who didn't buy the exp boosts will hit the level cap a day later at most.
If anything, the people who are getting screwed on this proposition are the people willing to pay anything for a tiny advantage. They are going to shell out tons of money, and not get any real benefit in return. People who fear that it will be necessary to purchase things in order to keep up or to remain competitive have nothing to worry about.