Fuji 50-230mm lens on X-E1/2
The gain you make from 200 to 230 is nothing that will make a difference to save $300.
Even worse the long end at 230 is f 6.7 and the 55-200 is f 4.8. Essentially the 50-230 is a stop slower maybe a hair more. If you think focusing is bad for any reason with the 55-200 it will not be improved under the same conditions with the 50-230.
If saving $300 is the deal breaker than so be it, it is your money and photography.
The same idea with a Nikon or Canon lens where the manufacture has two zoom lenses very close to the same focal length with f stop range differences.
If I understand the new Fuji lenses are optimized for the XA and XM. I have to check but each lens has a different designation either XF (more costly) or XC (less expensive)
I have to check but when you have two lenses like this with a big price gap you have to look at lens construction so far as the groups and elements breakdown to see what justifies the cost difference. It is usually a ED or a extra element to help. Plus the f stop difference.
I would not sell my 50 - 200 except for a faster zoom without a variable aperture. I do not think the 50-230 is a step up from the 55-200 and with lenses the cost also speaks volumes.