I was thinking about this just the other day, hopefully the Alarm modelling will get changed when the third party Tornado is finished.
Currently the way it works is way off, apart from the the lack of loiter mode the attack profile is also wrong. Alarm is design to home on the Side lobes of radars, when it is launched, it should go into a steep climb and then run towards the target at high altitude 70K +(possible why the in game range is quite low).
It should then attack the radar almost vertically, this makes it much more accurate than most ARMS and allows a smaller warhead. It also means that once it is over the target it isn`t detectable by the radar opearator and there fore less likely they will shut down.
It also has the ability to be programmed with a series of way points, so it could for example be progammed to overfly a series of know SAM sites and attack any that are transmitting.
I don`t know if it would be possible to write a script in game that sets a way point at 70K and have the missile target it, this would mimic the loiter mode? (with out the chute)
Very cool weapon, I also would like to see a more accurate depiction of it.