The melee companions (desert merc, Barbarians) seems to have a very defensive stance. they do not fight any monster further than maybe 10m-15m away from the player hero. If the enemy happens to run away they will chase and comes back after a few meters then chases again and back and forth. was fighting blood raven with a bow amazon with my barbarian merc and he's pretty much useless
most times they are too dependent on who the player is targeting and will only target that. they dont target the next monster beside them unless the player targets that monster. this kind of companion playstyle is good for the Rogue's but is really annoying for the melee ones.
and btw, in act III and above the only shrines i see are health, mana with rarely mana regen shrines and everything else are mysterious shrines. where are the defence, battle, gem and others? i get why portals were disable but why most dissappeared?