That's what mutations are for.
Oh yeah, please, let's go say "You can just be warped by out of control Essence or be a beastfolk, that's almost as good!" That's not at all restrictive to what kind of stories you can tell!
People, all you're doing is confirming to me why the Tell should not only be in, but why it should be front and center. Lunars have a weakness. How terrible, discovery by the Wyld Hunt is still a looming threat, to the splat
that the Wyld Hunt was specifically created to kill. Making the Realm a better adversary does not make the Lunars weak; it makes it clear why the Realm has lasted for centuries despite the 400 or so monster-gods who created an entire society to destroy it. This doesn't devalue the Silver Pact, it makes their personal nemesis a threat that can meet them on equal grounds even in their home territory. If it makes shapeshifting have a minor flaw-so what? Congrats, you have a minor flaw you might need a Charm or a bit of thought to cover, or can play off as a normal feature that only becomes alarming when someone realizes it applies across all forms, and even then by rules people would just notice it looks remarkably similar to other features ("Funny, that wolf's chin looked like it had a goatee like yours.."). I
like the modern Tell as a motif or a weakness, because it's the kind of thing that is easy to hide, but can slip out when you're facing another Exalt who knows what to look for.
(And before someone tries to say "But Loser Exalted!", can I remind you that it's also now explicit the Silver Pact is the reason why the Realm hasn't turned everyone into satrapies and cultures can show up outside their grip? "We shapeshift about as well as the Thing, and like the Thing we have a trait that gives us away" doesn't exactly sound like a devaluation.)
To be frank; Tells might need to show up to other shapeshifters. It's an excellent way to give away a mythological hand. Also, I feel the need to reiterate that "beast features" is
not the only Tell. Last I checked, Raksi's Tell is the fact her hands bend backwards when she's not paying attention. That's hardly "fox ears." My own "'mortal' graduate of the Heptagram" has abnormally large ears that remind people of portee ivories. These end up actually making him beneath suspicion, since everyone assumes (with his encouragement) he just has large ears. In his other forms, it just looks like he has large ears, or colored patches that look like ears. Even realizing that large ears is his Tell may not help, because plenty of animals and people have large ears - and if they have long hair or a hat, you may not even see their ears.