Panther requires a wild shape charge. But prowl is bugged. It is not meant to be infinitely usable. It functions differently at levels 6/7 than it does from 8 onwards. If we look at the level 6/7 version, which is the correct version, it is only to be used once per short rest (though this is also bugged and you can easily circumvent this).
All warlocks, wizards, sorcerers (draconic ancestry only) or any character of the dragonborn race can learn to permanently summon shovel as a class action. And you keep it no matter what, even if you respecced away from one of those classes. It's free and costs nothing at all, aside from the respec I guess.
You're over-simplifying panthers role. While it can start combat with invisibility for a surprise round, that is hardly the entirety of its role. And comparing it to bear is just not a good argument. Bear is probably the worse form in the entire game, if you don't count critters/badger. Goading roar doesn't actually "taunt" anything. It just applies disadvantage on attack rolls against your allies to effected enemies. To be honest, considering you have 12 AC and your party probably has considerably higher, it has less effect than you think since everything is already much much more likely to hit you over an ally anyways.
