Some folks here have GP shifters, some have just flipped the little lever on the shift shaft up to the top side to reverse the pattern. The geometry is a little funky that way, but it seems to work OK for people.
I've been riding a conventional "1 down-4 or 5 up" pattern for 28 years, so I'm not about to try it. I don't want to experience a full throttle downshift when I intended an upshift...
Some people can reprogram themselves easily, and enjoy the difference. Others have a little harder time. I think I'd be in the "nearly impossible" category.
For a while I was running Attack rearsets w/ reverse shift linkage on my R6, while my wife preferred standard shift on her S4. Switching between the bikes was not a problem, and I think I've only missed a shift once or twice (during moderate acceleration, thank God).
When I sold the R6 my wife gave me the go-ahead to flip the shift arm on the Monster (a 5-minute mod) and again, swapping bikes with friends who run standard shift has not really been a problem at all. What I like about the reverse shift pattern, besides the obvious ground-clearance-in-left-handers- issue, is that it provides a more positive upshift (false neutrals were never really an issue on the Monster, but they were on other bikes I've had) and pulling up on the lever to downshift under hard braking while squeezing the tank with my knees seems much more natural to me.
The beauty about the Monster shift linkage is that you can flip your shift arm, see if you like it, and if you don't, the mod is easily undone within minutes.
I really like the GP-Pattern more the the US standard pattern myself. I have a Fast By Ferracci Reverse shifter, that I had machined (shorted) to fit my M900. The lever connect directly to the trans. and gives smoother shift control.
I don't race my monster to the point that left side clearance in high speed turns is an issue, but it would help I guess. Monster shift linkage can flip in minutes, which is common with most Ducati.
I'd give it try (at low speed). If you switch, be sure to switch all your bikes to match. I have Ducati 350 Scrambler which has GP-Pattern shifter on the right side! Which always take me a few miles to remember.