Of course Makarna can be done with kata gear, how do you think they did it when it came out on retail? And what do you mean minimum 3900 MB ?
I think this is a great idea, it would add something to do for players who prefer PvE and are currently looking for challenges in the game. There are plenty of cool instances, but not many end game ones, and Makarna is both. It would also bring back some nostalgia and memories for those who used to do it on retail.
Regarding the gear, it is completely up to the admins if they prefer to add it to the game or not. Personally I think it would not be a good idea, as it would cause too much imbalance and make other end game instances way too easy. But even without the new gear and something like skins or manastones as rewards instead, adding Makarna to the server would be amazing and I really hope the admins can make it work someday.