I see deathstorms in every game i play now. Yes, literally every single game i play there's and least one space marine player, and he's going to build at least one deathstorm drop pod. Rushing to tier 2 to call in an early deathstorm seems to be the most popular space marine build at the moment, and it's no wonder. With the click of a button you can kill (or at least force away) your enemies entire army and take that vital resource point that you've been fighting over, no questions asked. There's virtually no counter-play, no counter-build, nothing you can do about it. When the space marine calls in a deathstorm in the early game, you get out, or you die.
Deathstorms could be nerfed in many different, and obvious, ways. Just mix and match between Reducing damage, Increasing cost, Reducing active duration, Reducing range, Increasing time to drop to give the opposing player a bit more time to get out of the way, etc.
However, i would go further than that and ask: "Why do deathstorms even exist?". From a game design point of view i find them incredibly dull and poorly designed. The biggest issue in my opinion is their "effort-to-impact ratio", meaning it takes VERY little to use deathstorms, but the impact is almost always going to be huge. There's simply nothing strategic or interesting about deathstorms, and no amount of nerfs is going to change that. There are a bunch of powerful and interesting combos to pull off in this game, but deathstorms are just not one of them. Click the icon, click the enemy army, watch them die or run away. That's it, completely void of strategy or tactics, offers little to no counter play, and is incredibly effective. It's nothing but a hugely frustrating element of the game that i honestly would rather see removed.
I do, however, realize that Relic probably won't remove an entire unit from the game, so i will point out that my favourite nerf among the ones suggested above would be increasing the time it takes for the deathstorm to drop. The opposing player would be able to see the icon for the entire duration, giving them time to react in some way. With this change, even if the time to drop would be very high (maybe 7-10 seconds), it would still be an incredibly useful way of controlling your opponents army movements, as they won't want to stand next to the deathstorm once it lands. If they don't get out of the way then they'll be punished harshly for it, but at least they had a chance to do something about it, which can't really be said right now.
I think space marines have a lot of tools to work with when it comes to overrunning positions and flushing out enemies, and it's a shame that their most effective one is the most effortless one.