There will be complain but I can almost guarantee you it won't come from neither of the sources actually matter.
- The people who prefer to buy it from mog station over grinding will most likely keep doing it anyway.
- The people who refuses to use mog station no matter what will still prefer to keep grinding.
I don't say they will be the only complainers, but biggest complainers will be the crowd who will neither want to pay (the everything should already be in the game for free crowd) nor want to grind for anything (the this is too mindless crowd), or in short the "I want everything for free and I want them to be given to me on a silver plate" people. Again, while the move won't affect them, it'll just give them a stick to beat with. And of course, you gonna piss off some part of the other two groups as well. The latter will complain it makes their effort meaningless now that people can just buy it with money, and the former may take it as a scam.
So no, I see very little actual benefit aside generating a ton of new forum drama (if you're into that sort of thing).