If oracles are going to have less spells, and have a cost for using their focus spells, they should be able to use focus CONSIDERABLY more than other people.
I, personally, think this means they should be able to stall their curse progression several times, put it on a 10 minute timer, in battle, the curse still goes up, but out, other focus spells dont murder the oracles utility.
The oracle focus spells also need to be more considerable if the final cost is ending the adventuring day. An extra cast is almost never worth going down, and you shouldnt have class features you not only wont use, but arent supposed to use.