I doubt a 200/50-17 will improve anything on your bike.
The advantage of the 190/55 over a 190/50 (and probably a 200/50), is the cross-sectional profile of the tire.
Below is a comparison between typical 180/55-17, 190/5017, and 190/55-17 tires.
Note how the 180/55 and 190/55 are more pointed than the 190/50, which is rounder/flatter.
The 200/50 will be similar to the 190/50, but slightly taller and wider.
The more pointed curvature of the 180/55 and 190/55 is what helps the bike transition into turns. The added tire height also raised the rear of the bike and slightly decreases the rake and trail, also causing the bike to turn in quicker
The advantage the 190/55 has over the 180/55 are two-fold.
1) The 190/55 tire fits a 6" width rim while the 180 is designed for a 5.5" width rim.
To fit a 180/55 tire onto a 6" rim requires deforming the tire, which not only stresses the tire carcass, but tends to flatten the tire, defeating the purpose.
2) A 190/55 tire has a similar profile than a 180/55, but has additional sidewall area.
What a 200/50 tire will do is raise the rear of the bike slightly, but it will still have a flatter curvature. So the bike will likewise not want to roll into turns as easy as a 190/55.
While it may seem minor, the difference between a 190/50 and 190/55 can be dramatic.
But once you get used to it, I doubt you will want to go back to the 190/50.