@Nillo
I didn't say that party has to have definite opinion of everything. Just that they should have available and if possible informed opinion of important national topics. Yes, they would probably handle copyright issues fine but how about serious economic questions, environment legislation, NATO etc.?
Because they don't have (and probably can't have since they are all concerned about mainly copyright) definite stances on other important topics, makes them hard to get decent amount of votes. They may get some people in, but it may not be enough to make any difference even in copyright issues (if other larger parties in power favor current legislation). And if they get enough people in to make some real changes, this comes up:
I wouldn't feel as confident in my decision to vote for the Pirate Party if they took a stand on every issue that landed on their table. Inevitably, I would disagree with the party about some things. It opens up the possibility of them doing things I don't want them to do.
I feel same, and pirate party have to be part of other decision making too. Since they don't have definite opinions on other aspects than copyright, I can't be sure what they will do with other those decisions (which I might not like).
In short I would vote them if I had to vote members for "copyright legislation parliament" or some other imaginary council which would decide how copyright legislation is made. I support their cause. Right now though I try to vote for a party which I think would lead my country best
as a whole. Yes, I have to make compromises since I don't agree exactly with any of parties. However, the ratio of good&bad(or simply unknown, as in this case) seems to me be against for pirate party (here in Finland). If I know the positive and negative aspects of party, I can make informed choice. With pirate party lot of their opinions for important topics are still unknown to me at least. I simply don't trust them enough yet to give them much other things to handle than copyright legislation. This may change in future and I'll vote accordingly

And even shorter: I think pirate party has informed opinion on copyright issues, but running a country needs informed opinions with many other topics too. So far I haven't been convinced by PP's ability to handle them.