Well, for starters, yes, I think the memory leak problems are finally under control. It turns out that AOL (Digital City et al) never saw them because they always run with the min threads and max threads parameters the same. In other words, they've tuned their site to run a serious number of threads, due to serious traffic, and have no interest in giving the system back if traffic drops because no one else uses the production server.
The memleaks happened with Tcl 8x when threads exited, Tcl 8x required a new call to release allocated memory and the AOL guys simply missed it because in their case threads live forever.
As far as speed goes, Rob Mayoff has contributed an update to AOLserver (AOLserver+ad12) that caches compiled bytecode so .tcl pages don't have to be recompiled for each request (Tcl 8x is byte-code compiled as opposed to Tcl 7.* and earlier, which was truly and agonizingly slowly interpreted).
If you get significantly slower execute times for scripts with this patch set vs. via the shell, then something's wrong and OpenNSd.org would like to hear it.
OpenNSD will carry this patched version, along with the memleak patch, as its base version of OpenNSD 3.x.
Lastly, AOL is still investing some time into AOLserver/OpenNSD and there's a code base for OpenNSD/AOLserver 4.x that look very promising.