I have a similar feeling toward "Bye Bye etc", Edward; out of all the episodes, that is one of the hardest to swallow. Of course, Theodore Bikel is a wonderful actor, but I felt much of the cast in that episode was a little over-the-top. One could say the same is true for "Old Fashioned Murder", with both Phyllis Brandt and Darryl, and I'd agree in regards to Phyllis. She's the one element that I feel is a weak spot in the episode. Also, the editing seems to be especially sloppy for the series, with for instance Ruth putting on her reading glasses twice in a row, in a span of only a few seconds, as she talks with Edward. Other than that, I feel, as I commented before, that it's a fantastic episode. To me, the soundtrack is one of the best in the series, and though I can understand the feeling about Jeanie Berlin being miscast, there's always the possibility her character inherited more features from her unseen father, rather than her mother and the other Lyttons.
Also, it's interesting what "The Columbo Phile" reveals about the origins of this episode coming from a story devised by Peter Fischer. He is hands-down my favorite writer for the series, yet his original vision, to me, seemed inferior to what ultimately became this episode. As you've alluded to, Edward, the tragic, almost desperate nature of the Ruth Lytton character really gives the story impact.

Yes Bryce. I think also there's possibly less of a cat-and-mouse battle between Columbo and Ruth. Many of his adversaries seem pretty obnoxious, and rather willing to play along with him, as a way of detracting attention away from themselves. They can be rather smug and a little vain, and all to eager to portray a rather false facade. However, one gets the feeling with Ruth that she, more than anything, sees the murders as a kind a statement. I'm not implying, for example, that she wanted to get caught, necessarily, but there appears, perhaps, to be longing of recognition on her part, that she's entitled to a life as well, and just as her sister has managed to cause her a great deal of hurt, she's not incapable of administering the same.
I believe the portrayal of Phyllis being almost cartoon-like in her eccentricity, was simply a way of showing the utter contrast between the sisters, within the time available. Celeste Holm's character may have seemed unbelieveably extreme in her fainting etc. but there's also a sense for me, that the comedy elements within her performance (and that of Daryl too) marks a nice contrast to the overwhelmingly deep psychological overtones of the rest of the story.
I never really saw an issue with the casting of Jeanie Berlin, either. She could just have resembled her father's side of the family more. I know plenty of 'real' families where resemblances between certain members of the family, are not always strong.

I had never thought about the Phyllis character that way before, but now that you mention it, Edward, it is a nice contrast from Ruth, and sort of shows that while Phyllis over-reacts to the slightest things, Ruth is very reserved, even though she has deep-seated anguish far more oppressive than anything Phyllis has had to endure. So in a sense, one sister has petty pain, yet responds to it mellow-dramatically, while the other has torturous pain, yet expresses it meekly. Well, until she reaches a breaking point and commits murder.
One thing I wanted to mention again is the music in the episode. It is very distinct, much like the themes to "Murder By the Book", "Ransom for a Dead Man", and "Any Old Port in a Storm"; these all have themes that are only heard in a single episode (although I believe "Ransom's" theme can be heard quietly as background music in a few other episodes). Also, much like the Patrick Williams scores for later shows, I feel "Old Fashioned Murder's" music really helps set the mood.