i had lightning guardian, and 60-70pts in lightning element.
i had almost 1k earth shards at end of beta, and almost 100 lightning shards.
conclusion, it has no impact :)
marmots drop earth shards alot, thats it. In gridania only fireflies drop lightning and wind i think (at low lv), and they arnt exactly growing on trees, which makes it hard to craft anything, with any class, since most need wind shards.
it wasnt until i was hunting lv 10-15 mobs that i got wind shards...which sux.
I think Fire element would boost blacksmithing, since there's a skill for BS, that stabilizes fire element in crafting. Maybe it makes it less likely to become unstable or such...Makes sense for a BS to use fire anyways ^^
For fisher pick water/wind, for conjurer you can stick to those too, and focus on using water/aero type spells.
then you can pick a guardian that has staff/wand as tool, and or water/wind as element.
Dunno if it has any impact though :)
I think just using equipments with +craft stats and such will have bigger impact...but well, only SE knows :p