This gun needs a buff full stop.
It just doesn't feel good to use despite the fact that IMO it does what it was designed to do incredibly well. Who cares about what the gun does on paper, If the damn thing doesn't trigger some emotional response, give that "shock and awe" factor, or carry some extreme level of utility the thing will leave ppl wanting more.
It just doesn't feel special to use as opposed to guns like sunshot/wrath of rasputin (big explosions and warmind cells everywhere), ace of spades (more big explosions), or even thorn (posion damage).
TLDR: The thing is boring and there are more fun shooting experience to be had else where. Especially in the exotic slot.
I know what you mean. I used it a lot when I first got it, it looks so cool and the sound when you fire it is pure bliss. I took it out last season for Harbinger, specifically the first "encounter" of the mission with the champions and emissaries. After dying several times I vaulted it and haven't used it since.
I missed out on Whisper back in the day but I remember hearing good things about it, so I purchased it from the kiosk this week. I feel the same way about Whisper as I do Malfeasance, it looks and sounds great, but actually using it leaves something to be desired. If I'm going to use my heavy AND exotic slot on a sniper rifle it should be POWERFUL. I'm talking one shot kill to the chest in Crucible (ammo per brick would definitely need to be reduced) and a complete annihilator of Majors in everything but end-game activities like Grandmaster NFs. Both Whisper and DARCI need a rework, either a significant damage buff or just put them in the energy slot.
I did the same thing in the Harbinger mission. I thought the thing would shine but I wound up tickling enemies and dying a bunch. It went back to the vault instantly. It's still kind of okay for pvp. Using it in gambit is a waste. There are much better options.