Why do you want it changed back?

The shard bombs are perfectly usable (but far from optimal) so I'm not surprised they'd pass through developer's hands without question. I doubt developers play the game on the same level as some of the player base and it's obvious from balance, or lack thereof, that they don't have intimate experience with all of the weapons in the game. It's likely that they just threw some numbers together and tried it out and found out that, for the most part, it does damage and can kill stuff.

From looking at the way the bombs operate, it is clear to me that they were unhappy with the way the old RSS delivered its damage: mainly its ability to hit a target multiple times (upwards of 8). The new bomb has been overtuned to prevent that and as a result sometimes it can consecutively hit for damage times over and over. I can see how a bug like this could slip by someone casually testing it because sometimes it'll only happen on one bomb then not happen again. In rare occasions it'll happen multiple times in a row but you're playing from so far behind (4-6s) that it's easy to miss bombs not doing any damage. I've only had 4-5 consecutive dud bombs 3 times in 2 weeks of testing so it'd be really easy to miss that.

Bugs should be reported via appropriate avenues (in-game, bug reports subforum). As far as balance goes, you can give this old thread a necro bump and cross your fingers that some changes will come down the line, maybe after the guild hall update or in 12 months.

p.s. Just look at the deadly shard bomb damage numbers to answer your question as to whether or not anyone ever thoroughly tested these. (spoiler: nope lol)

Disclaimer: this does not have to do with the removal of the old RSS. It is about the new shard bombs.

I managed to play around with Deadly Crystal Bomb a bit in FSC. My impression so far is that: this can be one devasting bomb for undeads if you use it right. Here are some observation:

• mother bomb's knock back could be bad when your teammates are nearby (it's a mini-nitronome); daughter bombs tend to obstruct vision;
• for best effect, lay several overlapping bombs. Problem is: more daughter bombs flashing around tend to obstruct vision (again);
• to ripe the upside benefit of the bomb (hence the only reason to use this bomb) is to have the mobs position between adjacent daughter bombs, while you position your next bomb so that its daughter bombs would lay right in front of said mobs. This way you would have 2 x 2 = 4 daughter bombs blow up. In theory you can chain explosion this way infinitely until said mobs are destroyed, resulting in 2 x N explosion (N is number of bombs laid);
• the bomb is a bit slow and no more one shot mob. Until today, I am still puzzled about why the developers are so offended about having an one shot bomb that requires skill to use.

Overall, I rate the new shard bomb 7/10. You lost 3 points there because of the unnecessary flashes, out of control knockback and trading off a slow bomb for a fast one (which is what bombers need).