Visas is really useful on the Sith raid so I can see why she has gone on a hard node but I agree her drop rate is horrendous I do at least one refresh a day on her and regularly out of the 10 attempts get only 2 shards.
The biggest difference to hard node farming was dropping back to 5 attempts a day. Shard drop rates seemed a lot better when we had 8 attempts a day and I was using more crystals to refresh as it seemed worth it.
They could do with changing the release cadence to speed farming up maybe put them on a hard node then after 3 months put them in either the guild store or guild event store as well so that people can speed up farming. Then after a year or so maybe make them available to the GW or arena stores and cycle toons through them