Hey all, Weapons team here!
So this is a pretty fun post to reply to, because it's a great example to show how far we have come and how difficult it can be to look backwards and see that progress has been made when it is incremental.
This week, the Immortal (Adept) had 7.2% of kills in Trials. From Week 1 of returning Trials all the way to Week 60, the number 1 weapon had:
LESS than 7% of kills only once (the lowest the top weapon ever got over the first 60 weeks was 6.2%, the next closest was 7.5%)
MORE than 9% of kills 49 times
MORE than 10% of kills 33 times
MORE than 14% of kills 10 times (Hard Light x2, Revoker x1, Felwinters x6, and Steady Hand x1)
In the ~80 weeks since then, we have done a pretty good job of keeping the number 1 weapon between about 4-9%, which is a very typical Trials weekend. We've had some exceptions of course, nothing individually has gone over 12%, but Jade Rabbit on Eternity and Telesto for that one weekend both hit 11%, and DMT during its peak and the Immortal (Adept) the first few weeks it was out were both around ~10%. But other than that the top weapon has been at less than 9% every week.
If we look back at the other times Endless Vale (arguably the most SMG friendly map) has been the Trials selection while Immortal has been in the game, back in April the two Immortals combined for 22% of all kills, then in May they were 15.5%, and this weekend they were 9.8%, so it's also not accurate to say that the balance changes that have been made to it have had no effect.
Last thing we'd like to point out: It's important to remember that Trials is not indicative of the PvP sandbox as a whole, and in fact it is very different than other playlists like Comp or Control. When we step back and look at the wider Crucible sandbox without Trials, the Immortals combine to be around 5% of kills, which has them on par with things like Ace of Spades and Centrifuse.
From, Destiny 2 Weapons Team