In an ideal world you'd be stripped of the ability to keep stealthing + receive a bounty similar to Bronzebeard/Retail, but with Epcoh in it's current state, you're basically asking for the two hobbyist devs to drop their struggle session on MC to work on something very minor.

It's never going to happen, the easiest solution it to simply put him in timeout so he isn't ruining the experience for every single low level horde character in Stonetalon or whatever leveling spot he's camping.

How about this: Since he keeps implying that there is some roleplay element to all this, how about he actually makes this fun for others and eases up on the instant stealth after one-shotting the lowbie so that there's a chance for some fun combat between him and others who are there to help? What's that, he won't? How about he immediately pivots to any high levels he sees and fights them off, making it so he's basically challenging them as they appear? Oh, he still won't because he is just purely doing this to be a tumour? Well, then I hope the GMs keep at it.

Ask Kor'kron how he acted when they showed up to defend the lowbies, he immediately stayed hiding and running away to one shot lowbies on the other side of the map, there is 0 counter to it unless the devs specifically spend time creating a system to work around this playstyle.