i CBF reading the rest of this thread but Spearhead apparently has a server setting that will allow admin to disable leaing while running.
apart from that i thought the movement speed was dictated in the weapon TIKs. i know theres another setting for crawl speed but unless you can eaily tweak either of those to change when leaning i dont think it will be worth your time this close to Spearhead.
The logic behind this was that not everyone will have spearhead and who knows, people might actually prefer the original game, so this would be for those people.
Its too difficult to disable leaning whilst moving, but I think it might be more reasonable to try and prevent the lean/strafe bind, I believe that this would stop 80% of leaners anyway.