There are a few ways that you can help:
- Maybe become a MediaPortal Donator.
Maybe give some time to making things work the way you want by changing the code.
Maybe give some time to reporting the items causing you a problem either as bug reports at http://mediaportal.elite-squad.net or as feature requests in the appropriate forum.
Try to be constructively critical as I'm sure you wouldn't like people aggressively criticising your freely produced work.
It's easy for someone to produce something if they work on it full-time and are paid to do it - many of the devs will already be software developers holding down a full-time job and presumably have enough problems juggling that with other comittments.
Be patient: things are getting better all the time!
But they will get better faster if you provide help in the appropriate way and ask politely!