It appears that there is a restriction on how many things you can vote on. This is counter-productive and goes against the entire point of the voting system.
How am I supposed to express my desire to have a feature implemented via the correct function if I cannot use it?
The idea is to make your vote count on the items you want to see implemented most. We might increase the votes as more feature requests are added, but I don’t see giving unlimited.
I agree, but I can also see it both ways. Already, because I know I have a limited number of votes, it’s made me be really judicious with my votes and only use them for features I’m certain I really want - which I am sure is the point. 
However, your point is very valid as well - what if I’ve used up all my votes (even being judicious with them, and not just using them on every whim), and then someone suggests a feature I really want? Now I either can’t vote for it, or I’m forced to remove one of my previous very carefully selected votes.
Like I said, I see both sides, and I don’t have a good suggestion. But just wanted to support your idea, as well as express that I understand why they’ve set it up the way they have.
Maybe the solution is to still keep it limited, but just increase the limit?
Edited to add: …and while I was typing this, @justin replied much better and more succintly than I did. 
Like @belovedjg, I can see both sides of the argument but overall I feel it’s better to have a plentiful number of votes (which arguably amounts to an infinite amount).
Having a restriction on votes makes voting into a weird zero-sum game. It’s kind of assuming there’s a set number of good ideas and it also doesn’t take into account the fact that ideas you vote for may be a good idea but something that will take a while before they’re implemented, meaning it holds your vote hostage for a long time; the alternative is you unvote for something that then looks less important/wanted as a result.
I can kind of agree giving limited votes to new forum users but I think once you’ve interacted with the forum a certain amount and for a certain time, the cap ought to be removed.
The votes will increase as your trust level increases in the forum. It doesn’t get to unlimited, but does get quite a bit higher as you remain active and engaged in the forums.
I actually think that’s a great compromise.
Unlimited votes ever for everyone is just about the worst possible idea.