Personally, I'd like to see reliability issues modelled into the game, one way or another. I don't mind random instances, and I sure don't get angry or pissed by something happening which is not of my own fault.
In my own opinion, reliability issues are also as much a part of the plane's characteristic as its climb, turn, accel, or etc etc.. For instance the late-war planes like Ki-84, while impeccable performance overall, was plagued with maintenance issues. Same holds true for some German planes. Others were also notorious for their own quirks - such as the early P-51Bs having a tendency to gun jam when the 50cals were fired at high G loads... or the F4U-1C had a tendency of the gun barrels freezing when it flew at high altitudes. The '41 Typhoons with problematic tail structure, La-7 with unreliable emergency power performance, and so on and on.
If the 'randomness' was too high, then it'd surely kill the game's fun. Like if I go fly a Ki-84 and its engines would malfunction, and give lower thrust everytime I fly it I'd certainly see it as problematic.. but if the probability was contained to a certain random limit.. perhaps 10%... where every once in about 10 sorties a Ki-84 might or might not have engine troubles.. then I think that would be acceptable as such.
...
However, I do understand HTC's basic premise with AH. I think Stoney summed it up quite nicely;
I think HTC's idea is to get rid of all the external factors and set the game up for performance based purely upon a pilots use of the planes as presented. Therefore, none of the "realism" of mechanical difficulty, weather, gun jams, bombs that don't drop, etc.
...and if that is what HTC sees with AH, I can live with that.
ps)
If there's one thing I'd really like to see though, is the removal of ammo counters. VooWho mentioned that introducing gun-jams would refrain people from spraying.. but the removal of ammo counters is far more effective in this. The reason people spray is that the certainty of the ammo count makes it possible for them to keep track of overall ammo spent, which allows them to take a calculated risk when firing their guns.
However, when ammo counters are removed, there's a great anxiety factor working each time you pull the trigger. No matter how much you count the seconds fired, you are never really sure how much ammo is left for you during the course of the engagement, and your entire sortie.