The only thing that
REALLY kills solo players are the commanders' stuns. They are just way too powerful!
This thing completely stops you (without GCD, a repair droid takes about 10s to START) and lasts for 20 seconds

And during these 20s, every single mantis is gathered on you because the commander seems to, logically, command them, often destroying a storm ship in less than 10 seconds, without giving the pilot a single chance. Let's also mention the fact that the stun charge has a rather low cooldown (~40s) and roughly the same range as
rockets
I like to take examples, so let's take a popular one: DIRTY WATER
Oh this story mission, bane of every Gemini pilot, and there's a reason why;
First, this story mission is quite long (no less than 20 minutes if you are efficient) and the last part of it is the hardest part, meaning that you always have to do it all again.
When you have to look for the third water purification material, it spawns in a spot filled with parasites, marauders and detonators, which is quite a big deal. But wait wait wait, there are ALSO 2 death squads meeting at this spot

, giving you extremely small, if not absolutely no chance to survive.
Well ok some story missions are hard, and hopefully they are, otherwise the game would have no interest if it was too easy

. No, the problem here are commanders' stuns being way too overpowered, thus making missions like DIRTY WATER almost undoable.
In my opinion, lowering either the power or the duration of these stuns could be a good solution to making the game more solo-friendly, but there is no need to lower aggro as Sirmorte mentionned, this is a matter of skill and game knowledge, like 'which mantis has the best aggro range?' and how to actually manage the aggro, kiting, etc...
Sorry for posting quite long posts, but I think this game deserves to get attention and I actually enjoy participating in making it better
