Good work, but you should provide more evidence. I did a quick test on my own and my spear hastati lost against legionaries (the normal ones, i dont know to which unit you refer with imperial legion since in my DeI translation there is no imperial legion). But it was really close and i admit the difference should be more clearly.
Of course i played on normal, so no buffs an such. No General involved and both charged with spear throw.
About babarians...this is a difficult question and has been discussed several times. Imo and personal taste: I dont think a roman legion have to win 1v1 against elite babarians, the strength of rome should be their formations, solid moral and durabilty. Since babarians lack formation button - which is already a downside in battle - they should be winning slightly against romans or at least a bit stronger (when the romans dont use formations). Please remember almost every roman inf has some formations -like square, which is super strong if used wisely - which increase their battle stats, many factions dont have that good formations.
Also you should be aware not to make all units even, because will get boring as soon as it is all the same. There is a point in the unique style of units and their weaks and strength in battle
3 waves of spears can change a lot and a thrown spear into head doesn't care about stats
Anyway. I will try your mod out. Thanks for your effort.