This thing has surely shifted around all over the place in terms of speculation of what's in it. It's
assumed it's about how the FBI used questionable methods to get the court's sign off to secretly surveil Carter Page on the Steele dossier, but it's not clear. There's an argument that the FBI would have been able to get the PC they needed to get a wiretap even without the dossier, but it's clear we're at a point where any and everything is going to be argued along party lines. There's no more Republican or Democrat "standard" and certainly no common ground. Just fighting to pit one party against the other and fighting tooth and nail to prove each other wrong.
What this memo did (hopefully), was point out the surveillance state we all live in and we, as Americans, have every right to know how our govt. is using its spying powers to investigate people with ties to our President. Unfortunately, this partisan bickering has gotten us to largely ignore the main issue here. Warrantless, domestic, spying of Americans in direct violation of the Fourth Amendment. If we're being honest, this memo will not spark a debate about that larger issue as arguments will be tailored around individuals.
It's worth noting that Devin Nunes is who wrote the memo. He's historically been very pro-surveillance, so it's strange he'd write it, but he's also a Republican and we'd be lying to ourselves if we didn't agree the "Memo" was a political stunt. The Democrats are, as you pointed out, changing their story, but let's also point out that Democrats did prepar their own narrative on what was in the memo but the GOP-controlled Intel Committee declined to release it, so there's only one side that will publically release their thoughts/beliefs of what's in the memo. It just so happens to be the same party as Trump. So, just as I'm not about to believe the Democrats are suddenly believing the FBI is the bastion of greatness, I'm just as apprehensive about the GOP pushing their narrative that the FBI is targeting Trump alone. Both sides are guilty of political posturing. Another issue, regarding Nunes, is that this memo doesn't have the actual intel in it. It's Nune's
interpretation of the intel used to surveil Page so we must realize that there's a good possibility the desire to release the memo is to benefit or protect Trump and that we're likely not getting the whole story. Why? Because, as you said, it's political but it'd be nice if we could see not only Nune's version of the intel, but the Democrat's, and the intel itsef would go a long way in terms of "transparency".
Regardless, this tiny bit of transparency (even if it is one-sided or political) may shed some light on how this secretive system works and even if the narrative is political, it's still a big deal that our own govt. is secretly surveilling people around the President and hopefully this reinforces the idea that the FBI is not what they pretend to be. The fact of the matter is (and I can't repeat this enough) many of the same people who are acting all "OMG, this memo!" about it are the very same people who voted to continue the program in question, including Trump himself. Personally, it makes one question their true intentions/ideals.
https://www.justsecurity.org/51385/releasing-memo/
I absolutely want it released, but some of us have been up in arms about this sort of spying for some time now, so it's not surprising.