Nobody seemed to even know who he was. That's strange.
Tragically, the writers and producers seemed to forget after that episode as well.. a well-timed Ed Haynes barb out of JR or even Cliff somewhere down the line could have really put Pam in her place or gotten under Bobby’s skin.
I think the reason they just dropped Ed Farraday Haynes in out of the bule was some of those early episodes were more self contained.
The Ed Haynes character was important because this episode brought out four interesting themes:
1) Bobby immediately chose the Ewing family over Pam when the news first broke. That was the first thread coming undone in the Pam and Bobby love story.
2) Once Bobby came around, he teamed up with Cliff to find the truth. This showed that while the feud was enjoyable to watch, Bobby teaming up with Cliff was even more enjoyable to watch.
3) Self-righteous Sue Ellen is ready to pounce on any weakness she sees in Pam and Bobby's relationship. She points out that the church board is concerned that Bobby can't keep a marriage together. This is in contrast to the healthy marriage enjoyed by Sue Ellen and J.R.
4) Digger Barnes stood up for Pam and confronted Haynes. This has some real meaning to it. Digger could have quietly stood by, hoping this would doom Pam and Bobby's marriage. He didn't do that. Digger wanting to come to the rescue showed he wants what's best for Pam, even if it helps Bobby and by extension the Ewing family.
It makes for a nice self contained episode because if you've never seen Dallas before you can stumble into this episode and get an instant scorecard.