I'm not quite clear as to what you're asking.
If you're asking "How can I help with Wiser Orcs?" That largely depends on your skills. If you're familiar with XML and python, I could really use help after the next release - I'm presently working on something which should have a major impact on AI strategies - specifically exposing a significant amount of (new) AI into the XML and Python layers. If not, I hope to have a write-up in the strategy forum within the next day to help me design the Python code for this; responding to that questionnaire would help.
If you're asking "Can we insert change X about mobility into Wiser Orcs?" The answer is probably yes, although the change would take more time than if it were in its own modmod.
If you're asking "Can we insert change X about mobility into its own modmod?" The answer is yes. In that case, I'd likely have you do most of the testing, unless it requires code.
Note, however, that if all you want to do is to move Mobility to Stirrups, [to_xp]Gekko gave good instructions for how to do that. All you'd need to do to change that into a modmod is to zip up the modified file, and post it appropriately, with instructions on where to place it.
In any case, assuming that you're referring to the second or third options, I'd need to know what your proposal exactly is. I think it's either to remove Mobility I and II entirely, or to move them back into Stirrups. Either of these would be easy, as they're pretty small XML changes. Depending on your preference, I can either describe exactly how to do it yourself, or I can do it. If you have further changes in mind, I'd suggest the former (so you can start to learn how to make changes yourself); if this is the only change you have planned, I'd suggest the later.
