An all shooty list won't work. It will put out some serious damage and can cripple and kill a lot of models but it won't win you any games. Part of the fault is that the game of Warmachine/Hordes is heavily geared towards close combat. The clearest example I can cite for that statement is that a Warjack/Warbeast can get extra attacks in close combat by using extra focus/fury but cannot do the same with ranged attacks.
There are precious few exceptions to this rule, I can only think of 1 in the Cygnar faction book that can get a single extra attack with an extra point of focus.
This statement of mine doesn't suggest that shooting is worthless. Hardly so, I've won games with a couple of well placed shots at an exposed warcaster. I am suggesting is that an all shooty list isn't going to work. What will work is a well balanced list with a more or less equal amount of shooting and close combat ability. Let the shooters do what they do best, pick off the weak supporting ground troops and exposed warcasters. The close combat should be left to the specialized infantry and warjacks who can be given extra focus.
That should work. If it doesn't then expect me to post my frustrations again.