For purposes of balance, I'll be comparing it to the AA turret of the Allies. In this regard the Sam Site has three weaknesses.
1. Slow Projectile
The Sam Site fires a slow projectile that takes time to reach its target. This means an aircraft can accomplish its goal before being shot down, and sam sites can overkill.
2. Projectile Timeout
Once on target, the missile can time out like any other missile. This means an active player can usually save their aircraft, especially with yaks or migs.
3. Small Range
The Sam Site has 7.5 range (radius) compared to the AA gun's 10. This means as a static defense it actually covers very little ground, and requires multiple sam sites to simply cover a small portion of the base. A player with hinds can easily maneuver around sam sites and pick off targets of their choosing.
Of these three, I think the small range is really what kills the Sam Site. An AA defense should act as an aircraft deterrent over an area, which it really can't do with such short range. At best it can be plopped down right under aircraft and score a few kills, and then be useless until sold.
To fix this, I'd suggest a modest buff of increasing the range from 7.5 to 9. It would still be fairly weak, especially when compared to the AA gun, but it could at least see some use in special circumstances.
I know the discussion will probably derail into air balance discussion, but if we could keep it to Sam sites that'd be great.
![Shifty :shifty:](./images/smilies/shifty.gif)