how fast do you need to be? rsyslog has been measured at 1M logs/sec for fairly trivial situations (which this would probably be).
however, I'll bet that you are really talking about much lower data rates, I'd be surprised if you needed much over 100 logs/sec and amazed if you need over 1000 logs/sec (remember, we're not talking about logs from the kernel here, we're talking about logs from userspace, the type of thing that is sent to syslog on a traditional linux distro, or is written to a app-specific log file)
the fact that the kernel is involved at all is simply a desire from the android developers to avoid having a userspace daemon.
for the trivial capabilities that the logger currently has (listen to a filesystem name, accept anything written to it into a circular buffer, and regurgitate the buffer if requested), it seems to me that a pretty trivial userspace daemon should be able to do this. I still haven't seen any explanation (other than the "we didn't want another daemon running" one) for why the kernel should be involved at all.