If a wizards familiar can get better, then so can a rangers! How about this?
Improved Animal Companion
You can master the toughest beasts. You beast companion can now be any size, and it’s challenge rating may be up to 1/2 your hit dice. It may be any type, but must be alive and non-humanoid. It may not have an intelligence above 6. It does not gain your proficiency bonus to AC, attack, or damage rolls. If you beast has the multiattack power. It may only make multiple attacks when you use the Beastial Fury power.
Thoughts? Is 1/2 to much? Would 1/4 be better?