First off, I think that the various enchanted weapons should require that you be able to produce the mundane version of the same weapon before you can produce the magical version, and I think the magical version should require metal and crystal. I might also include enchanted versions of each level of armor, available when both the Warfare tech unlocking the armor and the Magic tech unlocking magic armor have been researched, which have crystal costs in addition to the resource costs of the mundane versions. The enchanted armor and enchanted weapons should be superior to the base items, as well as to the magic weapons and armor at the same tier as the base items for the enchanted equipment, as a reward for the greater research and resource costs to the enchanted items and to reward delving into both the Warfare and Magic trees.
Then, to make up for the loss of weapon availability in the Magic tree as a result of that, I'd add improved versions of the Monk's Staff and intermediate versions of the Fire Staff and Ice Staff, as well as a set of Lightning Staves, perhaps including melee versions of these (though I think that the improved versions of the Monk's Staff would probably be good enough here), and I'd also expand the magic armor robes (including giving the second robes at least the same dodge bonus as the Monk's Robe).
As far as end-game repeatable techs go, I might give Warfare a set of techs which boost dodge, defense, and accuracy, as a kind of complement and counter to the late-game repeatable Magic techs which boost damage, although I'm not sure about that, since late-game elite units sometimes seem to have too much health as it is, if you can get a few levels on them. Might also consider going for a paired set of techs, one in Warfare and one in Magic, that increase Spell Resistance and Spell Mastery, but again I'm not really sure about that.
If the tech trees were to be significantly revised, I would like for each of the weapon types (both magic and mundane) to be split out into separate lines of development - one line each for swords, axes, hammers, spears, bows, fire staves, ice staves, lightning staves, and monk's staves. Possibly also separate research lines for armors, as well - a line for magic armor (the current robes and cloaks, plus perhaps additional higher tech versions), light armor (leather and further development of it), medium armor (current chain and masterwork chain), and heavy armor (current light plate and plate), although there are currently too few armor types to really justify this unless everyone gets to have all four forms of mid and late game armor (light plate, chain, masterwork chain, and plate). Then have an enchantment line that, assuming you have access to mundane weapons and armor of a given tier, grants access to enchanted versions of those weapons and armors. Each of the weapon lines would then get a repeatable damage-bonus tech associated with its damage type at the end of the line (swords and axes would share the cutting damage booster, spears and bows would share piercing damage booster, hammers and monk's staves would share blunt damage booster if possible, magic staves would have fire/ice/lightning damage techs at the end of their lines). Similarly, there would be defense-boosting techs at the end of the armor lines - magic and light armor sharing a dodge boosting tech, and medium and heavy armor sharing a defense boosting tech. Note that the damage and defense boosting techs would have an "either or both" prerequisite, rather than a both prerequisite, so if you wanted to boost cutting damage but didn't want axes you could just research to the top of the sword line and ignore the axe line.
As far as the once-off strategic movement increase tech, I think it would be useful, but I don't think that the game currently allows for distinguishing between mounted and unmounted units when deciding who gets the bonus. It would still benefit infantry more than cavalry, and the relative speed difference would be reduced, so it might work well enough anyways.
