Good points.
Yeah, I get what you're saying about damage ranges. I think the only reason why I'm leaning towards the way it is now is that in the way it's currently set up, if you had it set up like the way you're talking, you would ALWAYS hit the person and I want there to be at least a chance that you would miss.
In regards to the more reliable way of upgrading, one path I had considered was for specialization reels, where as you go through you'd find reels that could swap out with your current reel in the slot machine OR you could just sell it for <x> gold.
Thank you for your feedback