In my humble opinion both albums sound generic but for different reasons.
Ayumi has become too comfortable with her productions and it shows. Ayu incessantly releases what is expected of her and "Love again" is a prime example of that. It gets tiring after a while. I dont' feel Namie brought anything new to the table with "FEEL" aside from her obvious accent. She basically jumped on the "what's popular" bandwagon and the album seemed characterless because of it. She didn't focus on making herself stand out as an entertainer and followed what others were doing instead.
However, Namie is the only major female J-pop singer who goes out her way to change her sound at the cost of extreme criticism. I applaud her for that.

That automatically gives her the winning edge for me.
"FEEL" wins in my book.