Well... I already said the secret for having shards (Without RMT and gathering)
But here comes a idea that I think is a good idea and fair...
Make level 50 nodes where you require of some gathering % such as for example the same % you need for grade 3 topsoils. In those level 50 nodes add that every swing gives 10 shards or so (Put an example quantity, of course it could be more or less, don't kill me). It is good idea and fair because you make it useful to have a gatherer with some melds, it kinda looks pathetic to see a gatherer with that in 30 nodes taking shards in a slow pace, to be honest.