What is the difference between using present subjunctive and imperfect subjunctive?
Would you agree that the difference is that in the mind of the speaker there is a more remote chance of objectivity when choosing the imperfect subjunctive than when choosing the present subjunctive? For instance:
Ojala mis perros esten entrenados. Ojala mis perros estuvieran entrenados.
The first example paints a picture of a person picking up her dogs from the trainer. The second one, could be the case of someone who has never tried to train the dogs nor has the intention to ever try to train them.