"armor protected from glancing arrows"

An English (or Welsh!) Longbow could have a pull of up to 100 pounds with a draw length of about a cloth yard - that's a lot of kinetic energy! and fitted with armour piercing points was lethal against plate at quite a distance (if square on) - (and at 45 degree elevation, you get quite a range!) - it is recorded that such an arrow could pierce armour and 'staple' a guy to his horse at quite some range....

Hand drawn crossbows can only pull so hard - and the draw length was shorter - but when you have mechanical assistance, which culminated in ratcheted windlasses, you cold easily get as much power as from a longbow with considerably less strength training. Of course such Roman weapons could easily send a 6 foot long spear thru someone, armour or not ...

Chain was intended for glancing sword blows - a mace - mass weapon - inertial crushing impact - or axe - (largely mass crushing impact) would not be pleasant. Two handed swords could cut thru also.

The best way to avoid injury from a blow is to not be there .... :-)

Having knitted chain, and worn it, I can say that since it distributes over one's body, and was bound at waist and arm points, it is easy to train up - even modern Marines/SAS guys carry more weight.

"That pretty well ended the wearing of full suits of battle armor."

But they still LOOK cool ... and NASA researched just how well the joints worked when designing space suits. Anatomy hasn't changed.