To be perfectly honest, even in the best seasons of Star Trek (any series) there are always only a handfull of episodes that are genuinely "great". That's not a problem - that's the nature of art and entertainment.
If the rest is entertaining and watchable, one or two great episodes per season is really more than anyone can ask for.
If the rest is entertaining and watchable, one or two great episodes per season is really more than anyone can ask for.