After a year in sphagnum, it's probably time for a repot - for an Oncidium, a fine bark-based mix will probably be better than sphagnum.
You'll definitely want to start fertilising; that might be one possible cause of droopy leaves - but as it's in sphagnum, check the roots for healthiness ASAP.
I haven't had a chance to take a look at the roots yet, because we haven't been to the store to get the materials we need. We're going to hit either Lowes or our Lukas nursery again this weekend to get plenty of orchid pots, mix, and the like so that after my other two finish blooming, I can repot them as well.