Well to start with, i'm gonna leave my bias at the door......BIG Tara fan here.
Tara and Willow was one of the most beautiful romances i have witnessed on TV, and to me personally, the best one on the show and its sister one Angel. It came from a pure, honest place of love, trust and honesty.
It was gradual build of two people into a relationship i don't believe either of them anticipated.
Tara herself gained so much from this relationship. The main things were confidence and acceptance. If you compare the the Hush Tara to the Seeing Red Tara and dotted points along the way you will see that.
She gave Willow her everything, loved her completely, unquestionably and totally, BUT this had a mixed reaction on Willow.
Now this in turn had two effects on Willow. It gave her the confidence to explore the Magics, allowing her to delve into the 'dark arts'. She also became complacent, trusting that she will always have her tether, her love, her Tara, and when she is faced with the prospect of losing this she immediatley turns to a Dark place, basically suggesting a unhealthy aspect to what we all perceived as a beautiful relationship.
The second time she loses her, she again falls to the magics, this time she has someone 'egging' her on, in the form of Amy. Both Witches cause mischief and mayhem, while delving into the sinister side of the Magics, sending Willow further down a life spiral then she had ever been.
Ultimately though, one thing saves her. Hope, hope that she can, one day, return to the arms of her true love, that she can feel safe and secure again.
Finally, Willow achieves this, she fights her addiction, which we are told is near on impossible, she survives and receives her Prize. Taras open proclamation of Love. She has everything she desires at last, her love, her control, her life, for this to be taken again so quickly.
This pushes Willow so far over the edge that there is little chance of her salvation. The dependancy on Magic returns full force, taking out any reason the Witch had, all because she was dependant on Tara.....People say that the Magic was a drug, i personally believe that Tara was too.
Now Kennedy(you are not gonna get as long a comment). This character initially was built up to a gay character that i should have liked. She was strong, confident and new what she wanted. She was not ashamed of herself, her sexuality and her lifestyle, and this should have been a positive influence on Willow(This is poor writing of the Kennedy character). Instead, we get this self obsessed mish mash of gay stereotypes practically forcing herself into the affections of our Willow. She was pushy, but then so are many people in the Whedonverse.
Kennedy did come at a time, for me, too early for Willow, not because Tara had died but because Willow had lost her true love. You cannot simply get over something like that in a few months. I understand that we needed to see Willow move on with her life, and that later in the season there would have been little or no chance of Willow getting 'lucky' to prove she has come to accept who she is and whats she had, lost and regained.
So to finally answer your question i don't have one answer...lol
Tara and Willow we're soul mates, true loves, each others destiny's whatever you wish to call it, BUT Tara's power on Willow, though not intentional, was extreme, and not always in a postive 'my girlfriend has a pierced tongue' kinda way.
And with Kennedy, The initial character, would have been a great lover for Willow, opening up a side to her sexuality that she had yet to explore....but time constraints and poor writing never allowed that to happen.
So my answer would me......Neither was good for Willow, both were suited for the different Willows(IF Kennedy was written better) and Tara was the true Love of Willow....
I hope you read it all, and dang that took effort....YOU try being without bias when you detest a character as much as i do Kennedy...but i believe i did a good job....lol
