AH-99 has no advantages over Mi-48, witch is not logic.
Here is why - RAH-66 was designed with less armor than KA-52(for example), that means you can't just give them the same class. Not just because it is recon-assistant aircraft, but because of it's design. The result that was achieved by development team after decision to use significantly less armor was remarkable. Why ? RAH-66 Comanche helicopter has radar reflection TWO times less than AGM Hellfire. It is unfairly that in Arma 3, its copy - AH-99 has less armor than Mi-48 and can be detected by any radar. The idea mainly that there is no way engineers would give it less armor if the helicopter has no stealth capabilities. They also did't use wings for extra load to reach this goal. But in Arma, AH-99 has no advantages, and easily loses face to face with Mi-48 and also can't be used for recon-assistance because of radar detection.
It also has incredibly low maneuverability and survivability regardless Mi-48 witch can easily fly almost half of Altis without both engines and one rotor from 1000 m alt (with AFM of course)
My suggestion is to make AH-99 invisible for enemy radars as aircraft unit, but allow enemy radar to detect it as a missile and not always. Randomly and rare.