If it were up to me, I would use only broader suggestions.
Honestly, I can't be bothered to read three hundred minor suggestions that are for the most part just different takes on the same issue. I hate people spamming the Eternal list with minor things because it makes the list almost unusable. It's so large that when I'm in the second half, I don't even remember the suggestions from the beginning. How can I prioritise then? IMHO, the max. number of suggestions for the list to be user-friendly would be a couple of dozens, not hundreds. If you are concerned about usability of the list, G-Flex: it's length is a major issue. Wiping the whole list and starting anew would have the added benefit of making it small and readable again.
Voting for threads here in the suggestions forum would be even worse. There's eight thousands of them, you can't be serious!!!
With all respect, G-Flex, you examples I couldn't disagree with more. "Carry more items" is a horrible suggestion that only makes the list more convoluted, and is better served by "Improve hauling". "Separate bags from boxes" is a horrible suggestion that would better be included in a larger "rework the stockpile categories" or something. Also, I can't possibly vote for something as small as "carry more items", because it doesn't really solve the overarching issue of bad hauling, and as an isolated suggestion it's almost meaningless. The reason why the top rating suggestions are so popular isn't only because they're broad, it's also because they're well thought-out and useful. They usually link to a massive thread full of minor suggestions and a rich discussion, while also allowing some space for Toady's creativity - the popular Underground Improvements and More Mechanics are great examples. I really wish everyone would take the time to back up their suggestion by a forum thread with a well-thought system, nuances, etc., instead of posting each detail separately. If there's any problem with the current suggestion system, it's that people don't put enough effort into their suggestion before posting.
That being said, I wouldn't force any official limit on the broadness of suggestions. Let it flow naturally, the bad, small ones will naturally drop where they below - down to the bottom.
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The current system seems good enough to me. If there's anything I would do aside from wiping it, it would be:
- Force linking suggestions to a thread here. You wouldn't be able to post a eternal suggestion without posting a thread here first. This could actually prevent some people from spamming the list.
- Allow more votes. I still think limited votes are good, because we want people prioritising, but considering how many suggestions we have, perhaps increasing the number of votes to 5 would be nice. 10 seems like to much, to be honest. The number should be limited enough to force you to pick only a handful of favorites.