You will probably not notice much of a speed difference either way. Much of the slow down in WDL comes from executing acknex commands (trace, move, scan, etc) and not from the code itself. Of course it all depends on what you are programming. Some AI algorithms depend on things like recursion that can bring your computer to a crawl.

What "specific functions" are you missing from WDL that you need C++ code for?

Spark! is a interesting little tool ( www.louderthanabomb.com ). Depending on the type of game you could probably combine it with A5 to make some quick AI.