Other thing is that Legionnaire shields are reasonably breakable for Axe specialists, unlike Warrior shields which are a waste of time to try to break.
Yes, Archers are a lot less effective against the Ancient Dead, but they are not entirely useless when the Legionnaires come around; they still do full damage to armor, so they can still armor-strip the Pikemen. Which make them really easy to get chopped by a Greatsword or Warbrand user (via Split). Also, since the Legionnaires have really low initiative, it’s really easy to stack Overwhelm on them with your Archers. Heck, even full plate users can stack Overwhelm on them.
My guy with fighting axe makes pretty short work of those shields. Finding a named axe with high shield damage will be a lot more exciting than before now. Also flails are great since they ignore shield defense (20 on a tower shield), but their damage is not that great. Splitting shields and using hammers is probably more efficient.
As for archers: I still think they are amazing against legionaires. War bows pretty much melt their rather light armor (135-150 ish I believe) and overwhelm helps to keep your shield bros from getting hit by those nasty pikes.
I believe Legionnaire armor is somewhere between 150-200 (depending on if it is the scale mail or the breastplate). But it is still significantly less than the 400 armor that Orc Warriors get.