What would really make my day is the option to hide posts from Newbies and Jr. Members.
Why would you do that? In plenty of subforums newer members still have perfectly valid questions and responses. I only ignore two or three people on the forum and it's been like that for me since the day I joined. If an option for this was added newer members would find it even harder to earn merits to reach their next rank.
Spam is nearly nonexistent in some subforums and rampant in others. We simply need to add moderators to some subforums or swap out moderators for more active ones (much simpler than adding 20+ people in to look at everything posted, which would be almost unfeasible considering how many posts are made every second here), and a solution to revive spam-ridden subforums like Bitcoin and Altcoin discussion. Pretty much no actual discussion goes on there, just broken Google Translated English and pasted responses.
A solution for spam-ridden subforums would be the option to hide posts from Newbies and Jr. Members.
That doesn't change the fact that they'll just continue spamming useless posts (the only change being you won't see them), and in those subforums half or more of the people posting there are either member rank or up. Some more active moderation like I mentioned in my previous post would greatly help out the situation, and perhaps a sticky with rules regarding restating the same thing a million times would help. It's interesting to watch a thread with its question answered within the first five posts blow up to hundreds of pages there.
You are right, of course, the spamming would just become invisible, but I think knowing that people are probably not seeing your spam, might have a demotivating effect.
Or maybe a "reversed Ignore" system might work, in which you have the option to hide complete rank groups, but to unhide some of the people who post interesting stuff.
Anyway, as you said, not all posts written by newer members are spam posts - I would be a hypocrite for telling the opposite, since I was a Newbie myself in recent history... But honestly, I am almost a 100% sure that I would activate a filter f.i. in Altcoin Speculation and ANN threads and such, if that would be made possible. The current state of certain posts in certain subforums is just horrible, be it for content, or linguistic quality...
I think such a system would also take off a lot of the work and pressure of the moderators. And since no-one would be really blocked or banned, there would be no whining about freedom of expression and other blah blah of the likes of the current Merit whining.
But hey, just my two cents, thinking out loud.