The game at is core is crap, and nothing will fix that short of a serious overhaul.
Yep, that's pretty much it. What's really sad is the fact that paradox doesn't understand their own game or it's problems. Their new dlc (of course) and patch are great examples of that. They add a bunch of useless stuff ("New portraits! And they are cute! Lolz!!") or change some mechanics (sometimes for the worse *cough shipdesign), but neither addresses the problems in the right way.
For example, why would you think that the war-in-heaven-feature, something that should really be in the base game btw., would improve Stellaris when war and space battles are one of the games weak points: they are utterly boring!
Also, adding a bunch of story events, no matter how well written they are, will not improve the midgame, because once you have seen them a few times, you will click them away without reading any of the text. You will just pick the option that is the most beneficial to you and that's it.
The game needs more and deeper mechanics that give the player stuff to do without getting tedious.