I would hesitate to answer that.
I have seen people going crazy over some dots on some leaves/ thriving for the absolute perfect leaves with the green color just so - I could be looking at the same thing and scratch my head and wonder what that person sees. Totally yellow leaves will fall off and can be collected, or trimmed with a sterile tool without pulling off parts of the healthy tissue. Be aware that some Oncidiums ( see Sharry Baby) show many times spotty leaves without being diseased. Orchids grown in bright light might show a brighter green, some leaves will actually turn reddish brown and spotty - and that is ok for that particular Orchid and so on.
Btw Orchids in nature will look far removed from the perfect plant many hobbyists trying to strive for. That doesn't mean the Orchids in our care should be overgrown, sloppy, with crappy growth - I would strive for a happy medium regarding the trimming of Orchids and let the blooms speak.
