[tptacek]

I believe so. If you're memory-limited, then no matter what hash you use, you might be limited in how high you can turn the memory-hardness pain crank. But you still want that dial turned as far forward as you can.

But the situation you're describing is why all password hashes, including the three "legacy" hashes (bcrypt scrypt PBKDF2) are parameterized by cost factors.

[JanKanis]

But on hardware for which the hash function implementation is optimized, you will be able to crank up the cost factors higher than on comparable hardware for which no optimization was done. So a different hash with an implementation optimized more for ARM could give more protection than Argon2 on ARM because you would be able to use higher cost factors while still using the same amount of wall clock time. But I don't think such a hash function exists, and if not you could as well create a more ARM optimized implementation of Argon2.