My biggest hope for the new codex (or even a forgeworld IA) release would be for a Commander in an XV9 suit, and a couple of different weapon options for crisis, hazard and stealth suits.
Currently we can have a Commander with a SMS and 3 other options why not be able to take 4? Now that would kick ass.
Or if XV9 could take 2 double missile pods
The list of things we all wish for is probably quite extensive but if a stealth suit could take a rail rifle that not only would make sense but would kick ass.
Back on topic technically fire warriors and gun drones give more shots point for point (13 gun drones is only 3 pts more than XV9 with ATS which is 42 shots a Turn vs just 16 with ap-1) but both die much easier to small arms fire
If you fire 10 bolters at drones lone range would kill 3 on average, 6 at close range, but XV9 would suffer 1 wound close range and most likely no damage long range.
So back to the main point is that they are disgustingly cheap and effective for what they can do.