If you have to swap out the internals of a throttle, why would replacing the whole thing be any harder?
I have a Tommaselli quarter-turn throttle on one of my builds.Just make your own cable ends.
Every modern streetbike, and even a 79 Bonneville I've owned had what I would call a normal ratio, either 1/4 or slightly more. I'm not used to the one on this bike, which requires some arm and wrist contortions to really open it up. But it is probably best for the slow speeds the bike operates at. Maybe it's just a matter of conditioning myself to stop wanting to pin the throttle all the time, like on sportbikes....
Well, I hope it does stop you from wanting to pin the throttle all the time, or else you are going to wind up with a pile of oily internal engine parts scattered across the road somewhere behind you.