Here's my feedback, as gaming father, who spends time in this game to have fun, but also to be able to spend time with my kids - so see this feedback from a family perspective.
While I can appreciate the Kuva Lich system as something for the more advanced players, this has really struck a blow to my our families "fun time together". Let me explain:
I play Warframe with my boys. This is our fun time and family time. I dont get to see them much, so this is something we cherish.
As of the Kuva Lich system release my youngest son didn't fully understand the implications of going after one. After all, english is not his native language, and to top it off he's dyslectic. Not a great combo to have, when you try to read up on what's going on.
So now he has a Kuva Lich hunting him down and spreading his influence over the planets.
After just about 10 minutes of this Kuva play, he feels like doing something else. He wants to farm Ivara and do spy missions. When I explain to him that it's a bit pointless, as the blueprint will most likely be stolen from the Kuva lich, he gets very sad and says that he doesn't want to play Warframe any more.
And herein lies the root of problem with this system. It's thrusted upon players, in a way that is unavoidable (was at the time he killed the larva), unless you are fully fluent in the language and understand what your getting yourself into. If you not, you risk having a very bad gaming experience, that sticks with you for a very long time.
At this point there is no way he can kill his Kuva Lich. He doesn't have the frames, or weapons, or mods, or parazons to stand a chance. His gaming experience has completely turned from pleasant to this mountain of a chore and so family time have come to an abrupt close, as we scour the interwebs for something else to play together.
As a final thought and also a question to you. Will you implement a way for players, who never had the intention to get involved in the Kuva Lich system, to get rid of their Kuva Lich without having to go through the grind to kill it?