Apparently he develops this project alone. It is quite difficult for a single developer to maintain such a complicated freeware and opensource project. Especially if person has the job and the family when free time for any hobby like that becomes a very rare and precious resource, and furthermore when 3-rd parties add their own problems to the project - like the recent unstable AMD drivers. Not to mention of attacks against the pools - reliable protection costs more than those pools ever earn.
So this is normal he releases updates so rarely.
Unlike many other projects that exist due to money income, this one seems to still exist due to enthusiasm of one person. This rather deserves thankfullness even if result isn't that good as was expected.
Finally nobody is forced to use it, there are many else alt-coins. Also it is opensource - anyone could take part in development, but no one else seems to offer anything better for xpm.

I think writing constructive messages about existing problems may help developer to fix them. But simply negative feedbacks might rather suppress his motivation to proceed working on it, and barely may help to fix the problems.