Okay, this is how I think we might be able to fix the shard bombs.
The developers would have to switch initial detonation back to crystal bomb time, make the bombs that fly out from that do damage when they hit (like the original shards), reset the range of the shrapnel, make the shards not explode after it's already hit an enemy and make the bombs that fly out from the center do primarily knock back plus a little bit of damage if or when they explode.
They've really messed up this time haven't they...
Note, build on these ideas, they may be overpowered but I'm just putting this out there.
I was thinking something simpler; just drop the knockback from the secondary explosions, and replace it with knockdown like the Snarble Bomb and Magnus lines have. BAM! Now the shrapnel bomb seems less blast-oriented, and functions much better in parties.
What I've read suggests that shortening one or more of the timers (charge-up, separating charge, final warheads) and/or boosting the damage is in order, but that sort of knob twisting for fine balancing is beyond me; I'm a "gun and sword in accord" player to the extent that I can only offer opinion on very coarse adjustments like simple changes to dynamics. For what it's worth, I'd be most pleased to see at least the latter two timers shortened, but I am probably biased: the reason I don't get much into bombs is related to my considering guns to be essential melee weapons for the short animations and minimal movement disruption.