Because I have a broad sense of humor
1. The strange thing is that the writers managed to come up with good Kes stories almost up to the last minute of season 3, then all of a sudden they lost that ability. Must have been something in the coffee they started drinking between season 3 and 4 or........?
IMO, I don't know if I would call Kes' stories good because I don't feel they advanced the character in the way that they should. For example, I think "Elogium" falls apart because it begins to focus too much on the sci-fi aspect instead of tackling the more serious issue of teen pregnancy. I will however say, when Lien was given a script that focused on her character she stepped up and though her acting elevated a lackluster story to a better one. It's why I enjoy eps. like "Coldfire", "Before & After" and even "Fury" because they allowed Lien stretch her legs as an actress by stepping outside the limited boundaries of Kes' usual personality and display a broader range as an actress. Sweet and innocent was ok but I wanted to see what Lien as an actress could bring to the role and why she won the role out of all those that tried out for the part. The unfortunate part was those moments for her were few and far in between.
2. To answer your second question, I don't know. I'm not a mind reader.
But if we assume that she was happy to be dumped after three seasons, then she could have come up with a statement about it at the beginning of season 4. That would have prevented all kinds of speculation and rumors.
I know you're not a mind reader but as her fan, you know a bit about her personality.
If I could walk in Lien's shoes and empathize with her being the shy private person she was at the time, I don't think I'd be emotionally ready to speak to the press or to the public about being let go from my job. Lien in interviews speaks very little, in front of the public she barely gets out two words due to fright. I really don't think she had it in her to speak on something that was very private. Could you seriously go in front of a room full of fans or to the press about being let go from your job if you were depressed about it?
What I have heard , Jennifer was very depressed during the filming of "The Gift" and the other actors weren't happy over the situation either. If she "left of her own free will", the atmosphere during the filming would have been different.
I doubt that very much honestly.
Even if they gave her a party, it's never a joyous occasion have to say good-bye to anyone regardless of how it went down. Yiou don't work with people for 14 to 16 hours a day for 3 years and not feel something for them. If ANYBODY from the cast had to go, the atmosphere would have been the same. The scene in "The Gift" were Mulgrew and Lien are saying farewell, those tears in their eyes are real.