I believe if the staff members closing the threads would pay more attention to creating community interaction and promoting discussion instead of closing suggestions threads instantly and making the section look very closed off, then people and newcomers will want to make an effort to suggest anything for the forum. Instead the consistent, immediate closure of suggestions threads, without allowing community members to participate in discussions or to voice their opinions is negative towards the site. It's not welcoming and it's not nice to be stopped of voicing your opinion.
I would agree that if a suggestion is open for a time period like 3 days then people from all over the world at different time zones can make an opinion (except it being on DNS - which at times some people are allowed to create a suggestion and it remain open and things change on the forum 'cos they were previously not allowed and now is). I also feel like some staff members are slacking a meaning to do anything and simply close threads based on their own opinion. This is a community section right? How about you (staff members that keeps closing suggestions threads) interact with the suggestions put your own in and then let others, and after a while like normal mods do if the suggestion is negative for entire community you close the suggestion.