Except that hunter can revive/summon his pets while in that turtle shell you mentioned. Hunters can still cast everything from dismiss pet, revive pet, call pet, bestial wrath, mark of the wild, toss all 3 traps, etc while in shell. So you aren’t going to be interrupting anything when the hunter “gets back in the fight”.
Lastly Hunters have it no where as bad as a Warlock who’s minion gets focused and killed in a fight. not only does the minion cost soul shards to summon, it has a cast time far longer than a hunter’s revive pet.