From a campaign point of view....

When you can build pavised arbs (master bowyers) you can either build v1 arbs or v0 pavised arbs.... v1 arbs are better archers ... that's not even begining to figure in the slow speed's effect on positioning and the effect of fatique etc... (heavier armor = tire faster = shoots less effectie etc...)

Pavise arb's only advantage over arbs is the fact that they are the king of archer duals... but it's not like arbs are sissies in archer duals or anything... being high range high damage and pretty high defense for a archer... they beat most other archer anyway....

All i'm saying is... i find that in campaign that normal arbs tend to be more tactically and stratigically flexible.

Byzantian woulda acturally been pretty hard if the force wasn't with them XD.... (that and mass merc abuse) they start with a lot of border and very little troops/production capabilities... (they have one province that can produce most things but all the other province will take a while to get thigns going)

Anyway... the key to beating large empires in later game is usually agents and ships... try to collapse them from within (either with religion or spies etc...) and hit where they don't have much of a garrision (which is easy when u control the sea)