Ravenous Bugblatter Beast of Traal
That a direction. It's not the only direction. And it's likely not even the best direction because it only can handle the case of singular pets.No, actually, that's quite reasonable.
Why? Since it assumes the pet stays dead and now is replaced. A sad momentous event. It should not be possible to replace your dear friend just by snapping your fingers.
More importantly, the design should provide a robust pet that isn't significantly more likely to die than, say, the party Wizard. So this finding another beast shouldn't happen often enough to be a real detriment.
Let's take what you said: no more likely to die than the party wizard. If that's "the party wizard if they decided to run into melee" (which is where the beast is), then I'm good - and it will happen a decent amount. If you mean as likely to die as someone who avoids combat, that means that since they are in combat they are a large sack of HPs/Defenses and really as likely to die as a fighter. Being able to absorb a full character's worth of attacks and then come back with little resource spend is very powerful. When you combine it that without perfect focus fire it really means that HP damage is just spread around more, and HP damage is absolutely meaningless in the long term, that's a lot more powerful.