All you can really do is use the yield buff (about a 20% increase on total yield if used on extra gather nodes) or hit an area with double yield buff (though I haven't located one that has both double and extra attempt, double yield should give more over all though).

I agree that it's crazy that you only pull 1 shard per.

Crystals should be breakable down to 3-5 shards.
Clusters should be breakable down to 3-5 crystals.

Will this cause high level miners/botanists to be able to flood the shard market? Yes.
Will this force RMT to have to shoot for higher level bots and higher level areas to compete in the shard market? Yes.
Will banning a bot that's level 30+ gatherer have a greater effect on RMT bottom line than banning a level 5 gatherer? Yes!

I'm leveling all my crafting classes in tangent after getting armorer to 50 and realizing I needed at least the level 15 cross class skills to compete. I'm also leveling gathering classes to maintain my ability to supply gathered materials for these classes.

Once you hit about 20s, the amount of shards you need to gather compared to other mats reaches about equivalency.

Now that I'm in my 30s it's more than double. Just pulling a random recipe for weaving, which may or may not be representative of the overall whole:
Linen Chausses(33 recipe)
Total mats:
14 flax
40 shards

So gathering my own materials, I spend almost 3x as much time gathering what's essentially a level 1 material than I do the level 30 materials for crafting. And it just gets worse as you go on.

This is why RMT bots mining shards is so lucrative, because they're at almost max earning potential as soon as they put on a mining pick/harvester axe. They are almost certainly at a higher gathering potential on shards than a level 50 miner/botanist if they are using a teleportation hack, even if that miner/botanist is taking advantage of buffs and multi-yield nodes.

If you allowed crystals to be broken down into 3-5 shards then gather time for shards for a level 30 gatherer supplying a level 30 recipe would move to approximately even for shards:materials at 3 shards to about a third at 5 shards.

TLDR:
The fact that the ratio of gathering time spent on shards vs level appropriate materials consistently rises as you approach higher level recipes encourages wholesale purchase of shards. The fact that high level gatherers are less efficient at gathering shards than teleporting entry level bots gives RMT an advantage in this lucrative market. If crystals/clusters could be broken down, this would make high level gatherers more efficient than bots, reduce the time spent by legitimate players gathering shards, and possibly help curb shard market domination of RMT. Though this would have a negative effect on low level legitimate crafters trying to sell shards, it should have a net positive effect on higher level gatherers and crafters and reduce RMT profits in one stroke.