The new shard bombs are quite fun to use. However, in my opinion, they need some tweaking to truly shine. I suggest one of two these changes to help the bomb hit things more reliably (Bear in mind this was tested with RSS which was still 4 star, so suggestion 2 might be moot):
1. Fuse time of small shards is a bit long, make it shorter
Don't get me wrong, the fuse time of the bomb itself is fine, but the smaller shards take quite long to go off. I noticed this problem can be alleviated with VH-Max CTR, but it is still an issue. The CTR should not make up for a weakness, but rather make it better, if you get what I am saying. My suggestion is to either lower the time it takes for the small shard to go off by about 30 percent, or have CTR bonuses affect the fuse time of the small shards.
2. Explosion range of small shards is rather small, make it bigger
The small shards do low damage as it is already and their explosion range does not help that at all. If the range were to be increased, it would make it easier to hit with multiple explosions, even if its only with two, which would help the bomb's DPS. It seemed to work better on big targets than it did on small targets damage wise, which is why I suggest this.
The new bombs have potential. Also, I did not craft it to 5 star because I felt it was not worth it in their current state.
A very viable suggestion, and after seeing the new bombs in action, this could help tweak it in the right direction.