I would start reducing the amount of gas drops you give. I have heard that they can cause constipation, so if you are giving them at every bottle, that is probably too much!
Also, my little guy was fighting some bottles recently, so I sucked on the nipple to see if anything was coming out and sure enough it was barely coming out. I have gone through all the nipples and found two that were messed up. Now that we have eliminated that, he rarely gets mad at the bottle!
My first born did awful on good start formula. She was soooo gassy and I remember it smelling so bad. All babies are different, though. I hear ya on wishing things were simplier!!! I would consult your pediatrician to see what they suggest as far as formulas go.