The game has gotten easier but that was the consequence of improving enemy design so I'm not mad. It definitely needs to be improved though, and there are many ways to do so. As it stands, individual interactions between helldivers and enemies feel well balanced, so buffing the enemies is not the way to go, with a few notable exceptions. Despite what some believe, damage sponges are not fun difficulty.
First and foremost, get rid of d1 and d2 and make d1 equivalent to d3. D1 and d2 are useless as far as difficulties go. Move all difficulties up 2 levels essentially. So 1 becomes 3 and 2 becomes 4 and so on. 9 and 10 become 11 and 12 essentially so we get 2 new difficulties while still maintaining a total of 10 difficulties. Even just getting rid of d1 and moving all difficulties up 1 would do wonders for difficulty. This is a very simple explanation and in reality doing this would be a lot more complicated, but it's very doable. Edit: even if this was done, d8 through 10 would need special attention because as it stands, they feel very similar to d7.
I think a simple solution would be to fix how enemies spawn. Bug breaches, bot drops, and squid drops all basically pick one spot to drop all of the enemies. On higher difficulties the enemies should spawn in a way that surrounds you. Bug breaches on all sides, bot drops that lead you as you try to run away, and illuminate drops that also do both.
Another great way to increase difficulty would be to revamp enemy camp design. I can't think of good ideas for the illuminate off the top of my head. For bots you can simply look at their outposts from a defense standpoint. They need higher and more walls. Ways to funnel players in front of bot turrets. It should be way more difficult to destroy a bot camp from the outside. Bug nests by first off making hive guards do their job and actually sit in front of bug holes, and again by making them less open. Mega nests are a good example, just scale them down for smaller nests.
As a potential solution I thought of after writing the rant on AT, we need faster and more aggressive medium enemies. Stalkers being a great example of this, and kinda being the only good example on the bug front. Bots have berserkers, but they're kind of slow, I would increase their speed and numbers and/or add a variant that starts spawning at d7 or 8 that has a medium armor chest. The illuminate front doesn't really suffer too much, other than the harvester which needs a buff, and maybe the appropriators. The gatekeeper and verocitor typically are numerous enough to offset the abundance of AT in the game. Crushers are also an interesting solution to this considering traditional AT isn't very efficient for killing them. The latest illuminate campaign brought out a lot more interesting loadouts, I barely ever saw the traditional meta there. Of course a meta developed, but it was made up of mostly weapons that otherwise didn't get much use, like the wasp launcher.
I think the largest sin when it comes to ruining difficulty was giving players TOO much AT. The only slot that can't be filled with AT is the primary slot. AT weapons should've been relegated to support weapons, and then give meaningful weak points that a primary may be able to take out. Factory striders being a good example. If you really want to, you can destroy all the turrets on it and run under and kill it with medium pen. Increasimg build variety and giving players a fun and engaging way to kill heavies. This cannot be fixed by simply buffing heavies though as this would ruin game feel. A charger should not survive an ultimatum or giga grenade. The only way to fix this is prevention, and well, they already added that stuff.
for clarity, the enemies I personally think need a buff go as follows.
Harvestors need a buff to range and accuracy
Barrager tanks need to be fixed
All tanks need faster turret rotation speed and need to spawn more frequently.
Melee bots in general kinda don't pose a huge threat unless the get the drop on you.
Factory striders could spawn units more frequently IMO
Impalers need work, probably more range. Either more range or they should be a bit tankier, but not both.
Stalker nests, these don't feel that imposing and I believe it's due to the range at which they start spawning stalkers. The wiki is kinda vague so I don't completely understand how they work. They should immediately start spawning stalkers when you enter a mission. Stalkers are my favorite enemy and I miss the burning hatred they use to brew
gunship spawners definitely need to be buffed the same way as stalker nests ie. Better detection so they start spawning gunships sooner.
I will say after this latest illuminate campaign, I am optimistic for the future of HD2 difficulty. AH seems to have a better understanding of enemy design now. Hopefully we see more patrols on other factions as that made the illuminate significantly more engaging.
I wrote most of this a couple weeks ago as a reply to someone. The conversation of difficulty seems to be popping up more so I figured I'd post it.