I agree with Raissa, but exp to pokemons is good only to high levels, much players low level complaim to me the same problem, their pokes up more of 10 levels and they can't continue her hunt. So, i prefer other option of event, or give an experience time activable in every character (not sellable), is not a better idea, is just an example, but the question is, double exp only for pokes is not good for everbody.
with catch x2 such low level can catch several pokemons and exp them.