1. That's been implemented via signature bans. Global mods can decide if they give a warning (sig ban) or not.
2. No. Spam is not a trust issue.
3. Meh. It's already quite meaningless without proper enforcement.
4. No. Enforcement of forum rules should not be subject to voting.
old members who are contributing good discussions are kicked because they forgot to post a link when BTC was around $200.
I don't think that's true.