When thinking about my not very deadly shard bomb I started thinking of all the unique things about shard bombs:
1. Shard bombs get functional increases along with simple damage increases, like most weapons (larger radius for mist bombs, more explosions for brandishes), but instead of getting regular upgrades or one at 5, the only functional upgrade they get is going from 3* to 4*. Edit: Dread venom striker holds true for this point too.
2. Shard bombs come in every damage type. All other weapons have a maxium of two damage type options at 5*.
3. Shard bombs are the only types of weapons in spiral knights to have versions with both an innate damage bonus vs a certain family, AND a status effect.
4. Shard bombs have two types of 'bombs', with different damage, radius, and fuse time. The fuse time for the ring of shards also has a randomly generated fuse time (thanks Zeddy).
4.5. This causes the shard bombs to be the only weapons with unpredictable knockback.
5. Shard bombs are the only weapon type to have a hit limit. IMO, a hit limit would fit better on other weapons (cough alchemers cough).
6. Shard bombs are the only weapons that consistently match the color of their damage type, sans the specialised shards.
Personally, I think these things are a culmination of all the devs "wouldn't it be cool if there was a weapon that did/had x?"
Anthing else anyone would like to add/dispute/discuss?
"Shard bombs are the only weapon type to have a hit limit. IMO, a hit limit would fit better on other weapons (cough alchemers cough)."
If they ever did that, then Alchemers would need more ammo per clip to offset the loss of damage.