Roman Legionaries Vs. Medieval Heavy infantry

[Gluteus Maximus]

If the Empire had remained it would of adopted new tec advances and would be armed as well if not better than a middle age army. But if they had remained there wouldn't of been a middle ages!

...but the Empire DID remain, and while their territory and tax base remained intact, they were armed as well as any other medieval state. Whilst there definitely was a middle ages despite this, it could be said that in the Eastern Roman Empire there was no Dark Ages.

In this hypothetical conflict I believe the Longbow would have been decisive. So, against an English medieval force, the legion would not, I feel, be successful. However, against a Scottish army, reliant on schiltrons and light cavalry, the legion would be victorious for the same reasons they were victorious over hellenistic phalanxes.

Against a French/German medieval force Roman artillery would take out the Genoese crossbowmen before they got in range, and mop up the peasent footsoldiers without ceremony - but the knights would of course be a difficult nut to crack. Wether they would recover from a double volley of pila is interesting to ponder, and the feudal host was never disciplined enough to conduct organised flanking manoevres. So, I believe it to be at least feasible that the Roman legion would be victorious.

Taking the question in its pure context, i.e. specifically medieval heavy infantry against legionaries, then the legionaries would be victorious. After a few ballista rounds, harrassment from the small cavalry detail and two volleys of pila punching through the plate armour - before the close up stuff even starts - I believe the men at arms would find themselves outclassed.