Well, I'm going to be brief but I have to say, I like these new bombs. Went though with full mad demo and 4 slots full of shard bombs and simply went though the "Alien ooze" prestige mission. Even though it doesn't have the single target DPS it used to have, the shard bomb has some pretty decent AoE DPS, which well makes it a freakin bomb. Even though it's weaker than Nitronome or DBB, I feel that they're alot less annoying then them (yes I've had people in my party complain about DBB). One complaint I have is the that the fuse time for the second explosion is too slow. Slow enemies will get caught in the blast but faster enemies like mechaknights and gremlins will have no problem getting away. Overall, this would be a welcome change to the shard bombs.
Personally, I think RSS should be kept the way they are currently, with the 8 shards flying farther than a gun. If not then at least keep the split elemental and pirce. It doesn't have to be just a fiend killer, make it a darkness killer, just give it a undead and fiend bonus instead of a huge fiend bonus.