on my end it's two things:
i honestly find the theme thing an issue for me, it's so limiting (again, for me, i'm not speaking on behalf of anyone else)
also, timing is so complicated, especially nominating...imo too much time is spent in nominating a theme, then voting for one and when we're finally 'ready' to take the pic the next month's nominating/voting starts
too much bureaucracy for one picture of ONE theme if you ask me
taking pictures is one of the things i enjoy most doing with my pm, but if you ask me the photo contest on this forum has been the most complicated i've ever seen on a collectors forum
things can be so much easier, but i won't give advices unless requested