Python is a very high level language, which mean 2 things:
1.) It is basically pseudocode, so it is one of the easiest language for coders (of you have a list of functions permitted by the DLL, and it runs quite slowly. C++ is the other way around. It is harder to program (although it is also more similar to my fist programming language, Java, and not so finicky about white space. The big problem with C++ though is it must be compiled, so it takes a long time to get around to testing)
2.) It runs slowly.
No, my modmod is actually quite python-heavy. I've tried to code it as efficiently as I can in python, but it does unfortunately slow things down sometimes. I try not to use as much/as complicated python code for things that are used the most often.
(There is often a noticeable delay while it is doing the calculations for the Blizzard spell, which is probably the most processor intensive of my spells because it generates a seperate random number for each tile t cycles though. I don't mind so much for a level 3 spell though, and it doesn't look right is a 3x3 square of ice all melts at the same time.)
I would like to move a lot of it to the SDK, but that is beyond me at the moment. I can successfully compile a new DLL, have changed some minor things in the SDK before, and have even added a couple more functions to be called in python before (it compiled, but I hadn't tested my Temporary Feature and Temporary Improvement functions before a graphics change caused the game to not load properly), but my attempts to make changes in the XML schema have never worked. (I've been trying to convince Kael, Xienwolf, and Vehem to do this work for me.)