i would also prefer @ instead of ^ because its easier to understand when you see / read it,
and its use is known from other services (like whatsapp). im sometimes using ^ here to notify one
or more users and some people ask me why im using that symbol at all. i guess if it was an @ instead,
people would know why~
but yeah as stated in post #2, there is already such a function and you should change your suggestion to "Replace ^ with @ to tag user" or something like that
if thats important to you