I totally agree, unfortunatly a 3 months minimum is unfair to those who truly contribute, but those thread necromancers are just pointless. Perhaps there could be an hybrid. Say something where posts can be rated and if you post 5 positively rated posts in 45 days as well as 25 posts, then you can post on BST. If you can't achieve that, then 25 posts and 90 days. (or minus 9 days for each positively rated posts provided you got 25 posts with a minimum of 45days)should make a time on board limit aswell, like 3 months or something. people spamming old threads to get 25 post is bullshit and annoying.
And make it so that no everyone can rate posts. impose a limit of at least level 8 or 9(just shooting numbers, I forgot what it takes to get there).