That's not really "versatility" given that this is the only purpose for which Feral Fury is actually good. Yes, if you're facing down Voss and you don't have Crafty Assault, you might decide you need to play Feral Fury to take out two minions instead of three, rather than saving the card and not removing any minions. But if you then draw Crafty Assault, you feel stupid. Having some cards which are strictly worse for certain purposes than other cards essentially punishes you for being forced to act on that purpose now, rather than waiting until you draw the better ones.
And another damage boost, from Legacy, Ra, CR or many others (not to mention environments) makes it that much better than Stomp.
True.
Bestial Shift, Primal Charge and Natural Form's Power are worthless without a Form in play
But you will usually be able to have a Form in play for all but your first card play of the game, the only exception being against ongoing removal or loss of Power usage. Plus if you don't have a Form, Natural Form's Power can still be put into play for later use, so it's only six cards that are completely unusable in that fairly-uncommon situation. And they're more than good enough the rest of the time.
while Environmental Allies, Indomitable Force and Environmental Allies are not fantastic compared to a lot of others.
As I have said before I consider Environmental Allies (and also Environmental Allies) to be the least-useful card in the deck. Indomitable Force is pretty decent, though, as it's the only way you can get some soak while not being a rhino. Being a rhino is a little dangerous with it; you get another point of soak, but you also HAVE to get fire focused on you. Just last night I played a game where the Ennead forced Scholar to put Alchemical redirection into play, then hit him with two Sun cards for a total of 20 damage even through his Flesh to Iron (since there was a villain +1 damage in play, and five heroes). So having 2 soak is not a guarantee that you can survive getting all the area attacks concentrated on you. There are definitely going to be times where you're a Gazelle, frantically scrambling to recover HP after having been pounded on, and 1 point of soak while staying a Gazelle, slowing the damage you take even while you heal, is better than 2 points of soak while switching to Rhiono and painting a bullseye on your face.
This is part of the point of the Naturalist; that if you play a card while in the wrong form, then you're not going to get its full worth.
Crafty Assault, Threatening Stomp, Cornered Beast, Hyperactive Senses, Resilient Hide, and Eye of the Predator all provide more than sufficient utility even without their riders (indeed, Cornered Beast and Crafty Assault aren't necessarily any better, and Threatning Stomp is actively worse in a way; Hyperactive Senses can go either way depending on what the cards you reveal are and what you might like to do with them, though of course it's always better to be Gazelle since you can choose not to discard the cards). Indomitable Force is arguable, and Environmental Allies is situational. Feral Fury is the only card which is flat-out worthless if you're in one of two Forms, and only fairly good if you're in the third form. I feel confident in calling it his overall weakest card, though I still will pick EA as being worse in a fairly large percentage of matches. To draw a parallel with the Visionary, Environmental Allies is like Brain Burn - a very narrow but potentially lifesaving card, which I will happily discard 9 times out of 10, but would never want to actually take out of the deck. Whereas Feral Fury is like Cerebral Hemorrhage - a fairly tepid effect which certainly might come in handy, but there's another card in the deck which is almost always better (Psychic Maelstrom), as well as still other cards which tend to compare favorably to it (Mind Spike), and this entire category isn't even what that hero is best at.
Three copies, please! But during the game, the general value and utility of a card comes second place to what it can do right now - and that's what strategy guides are for, really.
I can see the use of a strat guide pointing out specific, unusual uses for cards, like we've been doing for Punish the Weak. Alas, the Naturalist doesn't really seem to have a lot of cards with those kinds of counterintuitive uses. For the most part, what Natch can do in any given situation is fairly self-evident, which is probably why the Guide as I've written it so far comes across as mostly stating the obvious. You have to give very specific examples in order to really meaningfully describe anything, and even then, he's straightforward enough most of the time that it can be hard to say anything terribly useful which the player couldn't have figured out on their own.