for my opinion decoder are way too common. they drop in numbers greater then you ever need and the market prices just show that.

i think decoder drop rates should be reduced by a lot. roughly something between factor 3 and 10.

another thing that dont has that much use atm is decoder merging. i realy dont know if the investment of that will ever come back, but its not realy usefull especially with the high decoder drop rates.
a suggestion for improving that will be to add decoder up to lvl20. these of cource ant be droped and can only be made by merging. now do the math... how many lvl1 decoder do you need for one lvl20. 20 would never realisticly be possible, but why limit it sooner?