I saw an interview once where she said that she started Here's Lucy to give the kids something to do.
Well, I'm sure there is some truth to that but I know she decided to end THE LUCY SHOW in 1968 because she had sold Desilu Studios to Gulf+Western sometime in 1967. Even though THE LUCY SHOW was raking in its highest Nielsen numbers during the 1967─68 season (it was #2 that year, right behind THE ANDY GRIFFITH SHOW), Lucy made it clear to CBS that she didn't want to continue in a show she no longer "owned".
CBS was naturally reluctant, but Lucille Ball wasn't about to leave television. It was her medium, the place she had done her best work. She just needed a little while to reconfigure things. What she and husband Gary Morton did was start Lucille Ball Productions and gently alter THE LUCY SHOW format into what they called HERE'S LUCY, a show CBS picked up without ever seeing a script or filming, screening, and testing a pilot. I think they agreed so fast to simply keep Lucy on television. They trusted her judgment, and things pushed right along.
There's a few different stories I've heard surrounding how Lucie Arnaz and Desi Arnaz Jr. came into the HERE'S LUCY casting pool. The most common one that I hear is the story Lucie Arnaz typically tells when she's interviewed about the show. She says that her mother wanted her and her brother on the show from the start, but they were both unsure at first. They each had other career aspirations (Lucie wanted to be a stage actress, while Desi wanted to sing and tour), but they eventually agreed to do HERE'S LUCY once their mother agreed to write them out of the show if word of mouth was negative towards their performances. Of course, we all know the kids did well enough (very well in some cases) and HERE'S LUCY had a six-season-run and enjoyed healthy ratings up until it concluded in 1974. Desi Jr. made fewer appearances after the second season, and doesn't make any appearances that final sixth season, but Lucie was there for the whole run, getting some real chances to stretch her talents when Lucy was chained to a wheelchair when she broke her leg while skiing.
I can't think of any show that declined in quality year-over-year as consistently as THE LUCY SHOW and with corresponding behind-the-scenes changes to explain the decline.
The first season is very good; not quite as good as I LOVE LUCY at its best but about on par with its average. The season has a focus and the comedy starts from plausible characters and relationships. Much of this is to the credit of Desi Arnaz. Although divorced for 2 years, Desi was still running Desilu and was the executive producer of the first 8 episodes of THE LUCY SHOW. Even after he left, the writers maintained the focus he established for the remainder of the season. This season is the last truly great work Lucy would do in her career.
Despite being a big hit, CBS executives were derisive about the series due to its lack of male stars -- one apparently called it "The Dyke Sans Dick Show". This is the reason Gale Gordon was brought in during season two. Without Desi, the writers didn't bother ironing out a good relationship between Mr. Mooney and the rest of the characters; any concept the show had became nebulous. During the same season, Lucy's belligerence towards her longtime writers caused them to quit. From that point on, her series would never again have consistent staff writers. The quality became erratic and any sense of continuity went out the window.
Vivian was miffed about the declining quality and feeling sidelined, so she left at the end of the third season. The change in direction between seasons three and four are so extreme, it feels like two different shows. Lucy, in her mid-50s, started being written has if she was a young lady and even the slightest pretense of believability was gone. As kinky as 60s TV could be, nothing is more perverse than the sight of Lucy in male drag -- a common motif in the series -- while still wearing fake eye lashes, blue eye shadow and red lipstick.
As grating and tacky as THE LUCY SHOW became, I would still take it over HERE'S LUCY which I find just about the stalest show ever made. Even the "good" episodes (the Burtons) I find to be unwatchable. I almost think I'd rather watch LIFE WITH LUCY, which at least has a kind of doomed valiance to it.
I'm inclined to agree with the majority of your opinions. Many look at the first season of THE LUCY SHOW as a continuation of I LOVE LUCY, and I can jive what that. That first season of THE LUCY SHOW is classic Lucy, even if it's something of a "step down" from what I LOVE LUCY gave us. Her Vivian Vance worked well together, and their relationship her gels effortlessly. It's beautiful how they compliment one another. It's interesting how Desi Arnaz and Lucille Ball continued a professional relationship after divorcing, and even after they each had remarried. THE LUCY SHOW started off strong and that's all to Desi's credit. He was the driving force behind I LOVE LUCY when it was on, and so he had a good sense of direction when it came to how Lucy would succeed on television.
THE LUCY SHOW was never really vacant of men, not even that first season. Dick Martin and Charles Lane were each a part of the cast, albeit as secondary characters, but I guess I can see how the network might have found it too feminine and felt the need to bring in some men. Dick Martin did well with what he was given, but his pretty much expressionless face didn't work as a "straight man" to Lucy's antics. He just grinned, but there weren't anything too animated like Desi Arnaz and Gale Gordon later gave us. Charles Lane was a good foil for Lucy, a talent he had shown in a few I LOVE LUCY episodes. The issue with Charles Lane wasn't his character or the writing, but his fear of performing before an audience. He and Lucy got along well and she apparently wanted to keep him around, but his sometimes paralyzing stage fright and inability to remember his lines eventually caused her to bring in Gale Gordon to replace him. (I've also heard that Lucy originally wanted Gale Gordon, but he was initially unavailable, so Charles Lane was just "filler" until Gale Gordon was free.) Either way, Charles Lane ended up moving over to PETTICOAT JUNCTION, where he played Homer Bedloe, the stick-in-the-mud that was always trying to shut the Hooterville Cannonball down.
The second and third seasons of THE LUCY SHOW still contain some good shows. I've been watching them on Hulu and I'm actually surprised just how much I liked some of those early color episodes. Lucy's still funny, and Vivian Vance is still around as her sidekick. Over time, Vance grew weary of the weekly commute to Hollywood from Connecticut, and by the third season, she was taking vacations which left room for Lucy to bring in Ann Sothern for a few shows. Before the fourth season, Vance bowed out altogether (but came back a few times later in guest spots). She was ultimately replaced with Mary Jane Croft, a faithful co-star of Lucy's. THE LUCY SHOW got trapped in its final two seasons. The celebrity guest stars were certainly crowd-pleasing and gave the show a shot in the arm ratings-wise, but it limited the stories. How many all time favorite movie stars can Lucy have? How many times can she get into silly situations with them? It got repetitive, but there were still a few good episodes to be had during those seasons, too. Few, but they're there.
As for HERE'S LUCY, I personally find it kind of refreshing when compared to THE LUCY SHOW. Yeah, it basically continues the story line that originated in the final seasons of THE LUCY SHOW, but I liked that Lucie Arnaz and Desi Arnaz Jr. were brought in to play her character's children. I guess I can understand how you found the show stale, but to me, I view it as slightly more mature than what THE LUCY SHOW gave us towards the end. Naturally, the writing on HERE'S LUCY is not stellar, but I overall like the look and feel that the show gives us. Once her children were phased out a little, however, it does become THE LUCY SHOW: REVISITED.
I've been watching LIFE WITH LUCY on DVD today. It isn't nearly as bad as people say it is, but it's far from being anything great. Lucy did far better work elsewhere, and it's really kind of sad that this was her swan song.