I see most here stating the restrictions are not high enough. I'd like to say the opposite. Bitcointalk should be about communication. I find forcing new users to spam five posts in this forum degrading. It potentially leaves a bad taste in the new users mouth.
I understand the problem, but, there should be a better way to approach it. For example limit one account per IP type thing. Tor/I2p/Proxy users would be sad, but, that is where 99% of your spam is coming from in the first place. Alternatively if you detect a multi-ip account (aka from Tor) then force them into the "newbie" class and to jump through these (even more restrict) hoops; fresh/first IP users should be exempt from this and go straight to JrMember.
An alternative here would also be to set up interfaces to the forums from I2P and Tor - I don't know anything about Tor hidden services, but for I2P at least it is possible to uniquely identify visitors (anonymously) with destination hashes instead of IPs, and the changes required to utilize them are normally trivial.