A few points, if you don't mind:
* Delta-v is low, the missile will have problems intercepting unwilling targets and intercept velocity will likely be low
* When it starts homing the missile typically orients at an angle to the target and then stops burning. This allows it to be easily taken out bypassing the armoured nosecap altogether.
* The missile is very large and heavy, making it easy target and preventing carrying many of them into the battle. With the above it makes it unlikely that even one will make it to even a lone, small, stock-equiped target.
* Flak+nuke is bugged - if you detonate the nukes on all missiles the target will blow up regardless of distance and orientation IF AND ONLY IF the camera is centered on the missiles when they explode and then jumps to target. If you pause, detonate nukes, switch to target, unpause, the target will suffer no damage or at worst light surface ablation.