I played some Beastmaster in order to really see if it is as bad as people claim and it actually is! I managed to level really quick to 55 with pets from Arena waves 50+ it got way too slow even with what seemed to be the options and gear from my level 98 character.
The survivability can even somewhat a little bit worked around if you do enough Strength & Glancing Blow stacking but the main problem is - BASE CRITICAL STRIKES.
There are plenty of nodes in the passive and skill trees which increase the critical strikes but the investment is far from being worth it for any pet or build because it’s too low - a mere 5%! This alone makes all the critical strike nodes useless.
If you’d increase the base crit to 20 - 25% through passive tree / uniques or just by simply having it as the standard, the pets would be capable of hitting much more through armor and leech enough to survive. The crit nodes would be a viable build option then as well!
I see this as the easiest fix for Beastmaster.
The second minor detail I’d add on top of it is increasing the Leap’s range to as far as Lunge aka whole screen.
And of course having pets skills cast instantly. I’d understand the cast time if there would be no mana costs but there are!