What didn't get enough discussion in that old thread (as far as I could see) was beast survivability.
Yes, you gain a hokey ressurrect-on-the-cheap, but there was too little discussion on alternatives that prevent the death in the first place.
I've always preferred Shield Other as a mystical bond between master and beast (ie not a spell), making it likely the pet doesn't die (from having no HP at least) before its master does.
I mean, when there is a TPK or nearly a TPK, sure, the beast can nobly sacrifice itself to save its master. But those fights are few and far between in 5th edition (once you're off the first few deadly levels).
The much more common case is that the fight is won with little to no mortal threat to the ranger. But as long as the pet remains much like an ordinary animal its survivability is in question - having many hit dice doesn't save the monsters, after all...
The stark reality is this: the pet is there to fight alongside its master. It therefore needs to withstand much the same heat the ranger is meant to withstand.
And many people are especially sensitive to animal suffering - it needs to be an explicit design critera that the animal companion should not die more easily than say the party Wizard.
Giving the player of the Ranger control over where damage goes (to the Ranger HP pool or to the pet HP pool) greatly alleviates this, and allows him or her to bring the pet to where it belongs: the brunt of the action, right next to its master.
Or, yes: in front of its master. Some denigrated the idea of playing a ranged Ranger and using the pet as your melee component. As I see it, that should be not only a perfectly acceptable way of playing your character/team, but one of the ways that make the most sense. Just limit the Shield Other to, say, 30 feet, so you can't cheese the effect by having the pet scout ahead.
Suicide scout runs, sure, but then Shield Other shouldn't apply.
