I'm going to jump into this Kes discussion quickly. 1st off, I happened to like Kes, and I thought that her actress did a great job.
Now, we now a few things. The 1st is that most Ocompa live to be around 9, and that a select few lived to be 12. We also know from Fury, that Kes was old, and senile.
That said, we know that in season 4, that she was around 3 years old, which means that she was around 7 or 8 when the events in Fury took place. We can't determine if she has an increased life span, but I'm guessing not, though perhaps she gained 1-2 years because of the events with the 2nd caretaker.
As for the fans, and the critics, there are always going to be people that like, or don't like a character. It's no excuse to be rude, or mean, as everyone has their own likes and dislikes.
The idea of energy sucking is an interesting one. We already know that Kes can make the flowers grow with her kinetic power, so it would make sense that she could also steal their energy. Weather or not that would help prolong her life, we can't be curtin.
Honestly, I think that it would be best if she didn't live to much longer. Having seen my grandad go through dementia, it's not a life that I would wish on anyone for very long, especially someone as sweet as Kes.
As for Q, like I said before, I'm not sure that he would be interested in Kes, and even if he was, I'm not sure that even a Q has the power to prolong life.
Also, he could have sent the ship home, but Q is not exactly known for his generosity, though he does sometimes do the right thing.