Yes. Pairing her with Ray was a disastrous decision - not only for the character of Jenna, but for Ray's character too.To me, I think the 1986 to 1987 season was when there was potential to keep Jenna on as a recurring character due to her pregnancy with Bobby's baby and there was no need to have paired her with Ray. Pairing her with Ray was the kiss of death for her character.
Had she been unattached when Pam had her accident and vanished suddenly, I could have seen Bobby turning to Jenna for comfort because of the fact that she was still the one constant in his life outside of his family. And it would have given her daughter Charley more of a motivation to be rebellious because she would be seeing her mother getting her hopes up for Bobby knowing that he would probably break her heart like he always did.
And perhaps Jenna could have still sent Charley off to boarding school because she was acting up, and deciding to move to live closer to her daughter and start a new life free of Bobby... but promising to keep in touch with him and have him be a part of his son's life.
That's how I would have handled Jenna's arc in the final season or two.
Pairing her back with Bobby after Pam's disappearance would have made sense.
If Ray HAD to be paired with someone other than Donna, I would have put him with Sue Ellen. Ray/Sue Ellen/JR would have been a much better triangle.