Like others stated, the problem lies in functionality lost, rather than moved away (hidden) from less comprehensible people and toward more comprehensible people…. After all, the system did exist and was already programmed, no need to take it away
Therefore, I agree with the idea of reimplementing the old custom-order system beside this new increment system, either as an additional input box on the conversion page, or in a separate tab within it.
As for more convenience than before, it should be made that there is a:
“Target spent gold” or “Target acquired Gems” for conversion from gold to gems, and
“Target aquired gold” or “Target spent Gems” for conversion from gems to gold.
This way, players can choose to convert in order to gain the amount they need of one currency, or convert what they are willing to spend in one currency into the other.
The old and new -could- be theoretically integrated through this as well by using the presets to auto-set the inputs in the custom conversion.
Also, if the graph was too confusing for the initial page, move it to a subtab, done.
edit: Thanks to Gaile for taking the brunt of this bulk, you personally deserve better than this. Didn’t actually encounter the frog back in GW1, but I recall hearing fondly about your doings back then.
) Then leave the old fine-tuned system as a separate tab or space… No reason whatsoever to remove functionality entirely. Period.