Oh yes please, that would be amazing.
Lindsey: 'Show Me A Smile? Who's that by?'

Not exactly relevant to this particular question, but I hope they add an August 6 show, preferably in New Orleans.

I think it's less LB is afraid to play the old Mac songs (he used to do them in the 70s) and more ego and the desire to get his own songs out there. You can find recordings of LB performing Green Manalishi, Oh Well, Hypnotized, Why, and others.

It's not just on LB. Stevie and Christine could take the vocals for one of the old songs. I always thought Christine would sound great on Black Magic Woman. It would be a nice way to interact with each other rather than just sing harmonies on someone else's song.

I Think Stevie could nail Hypnotized.

Hypnotized is such an amazing song, one of the band's all-time best. I didn't like Lindsey's version. But would they ever do this again? They have enough background musicians now to nail it. Is there too much ill will toward Bob, old grudges, ego to only do their own material?

I'd hazard a guess there's no chance. If they aren't going to play Hypnotized as a tribute after Bob's passing then they aren't going to start anytime soon. They still have it in their heads they must play 'hits'.
If Stevie quit (which I hope she doesn't) then a Mick, John, Lindsey, Christine lineup might have more scope for playing oldies.

they are not even doing their own material, aside from Rumours.

they just did 3 greatest hits tours in a row - if there ever was a time to do Oh Well, Black Magic Woman, Albatross, Hypnotized, etc, that would have been it (they did Oh Well in 2009, but not the latter 2 tours), so obviously it's not happening, unless they announce one huge all-FM-eras reunion. Mick had a lot of questions like that during m&gs, and what he would usually say is that he loves Peter and considers him the best guitarist that ever lived, and that he has tried that in the past, but Peter's health issues would not allow to reliably schedule any such performances or reunions.

so i don't really get all this righteousness and indignation of "why are they not doing other FM incarnations' songs". they are not doing even much of their own material, so why would one expect them to do someone else's? i just read on one of the other boards a question whether Peter Green's FM and BN FM should be considered 2 separate bands... in my opinion - yes. i was severely disappointed when i first heard that GH album in the early 90s featuring current FM incarnation - i expected songs similar to Peter Green era ones that i knew and loved, and that was nothing like what i heard. i listened to that album twice, couldn't believe my ears, and put it away for many many years, along with FM as a band i was absolutely not interested in.

they didn't play oldies as a foursome without Christine, who had by far the most hits in the current band, so i'm not really understanding your logic that they could easier play it without Stevie as a foursome? unless you think Stevie is the stumbling block (which i don't think she is, it's probably the whole band decision)?

There'd be a whole different dynamic with a Christine/Lindsey band. For Say You Will, Unleashed and 2013 they played up to the Stevie/Lindsey schtick. The draw of On With The Show is obviously Christine/the return to the 'classic' 5 piece. A Christine/Lindsey band would need a different angle. Such a band would be 75% blues-roots. Christine would need to play more of her own material and she has the pre-75 FM back-catalogue (as well as playing a couple of the new songs). Mick, John and Christine may be more inclined to persuade Lindsey to play an oldie.

see but they needed a schtick just because they were trying to make up some new excuse for touring greatest hits over and over again, the last 3 times.

they don't need any schtick if they have new music to tour (which they do!). if you envision next tour with Christine-Lindsey as only singer-songwriters, you would have all their hits and mainstays (which again, could easily be by numbers more than SN-LB led foursome if they choose to do them all since Christine has almost double the hits of the other 2), plus 6-8 new songs and you would have more than a full set.