Better to have mat traders than not to have them.
It's just that awful 6/1 and even more awful 36/1 that gets me.
I know I'll get savaged for this but those ratios are just SO Samarco/FDev design team; anything goes when it comes to wasting players time and effort. What the mat trader exchange ratio is really saying is simple: "Don't bother with anything other than G4-5 mats because nothing else is worth anything - except for the total waste of time requirement that demands you go through every grade before reaching G5."
To me - and I accept others will have a different view - the RNGineers and the associated mat-collection tedium means that engineering your ship is now the (almost) sole purpose of the game. Everything else seems to be inextricably linked with engineers...unless you want to ignore numerous activities in order to avoid engaging with the RNGineers, in which case there is little point in playing the game anyway.
IMO, the RNGineer revamp is a huge improvement on what we had before. The material traders could also have given a huge boost to the game.
Instead, FD designers clearly decided that what they gave with one hand simply HAD to be taken away with the other. Theirs is such a narrow view that, together with the various nerfs and scarcity of well-paid solo missions, the game now risks plunging into a never ending activity of scavenging, dull interaction with non-persistent, poorly identified USSs...and of course shooting Handwavium Voodoo rocks - which never even give the same thing twice.