It would be ideal if we could get Masked Rider to return via PR again. Acknowledge that "A Friend in Need" DID HAPPEN even if there is no intention of referencing the series it spawned. However, for this to be truly effective, Saban would have to obtain the rights to Kamen Rider Dragon Knight and then implant those characters into PR.

Using some of the recent revival productions of Metal Heroes is also worth considering given that Saban was willing to go all Netflix and Shout Factory with VR Troopers. The only one that would be viable is Next Generation Shaider, but the Return of Ryan Steele would be more than sufficient.

Toei will never let Saban touch Rider again. Ishinomori HATED Masked Rider and forbid Saban from touching his bugmen ever again, and the Japanese respect the dead too much to violate his wishes.

I'd create a number of miniseries detailing the creation of the 15 Sentai before the MMPR, either by Zordon to aid in his fight against Zedd, Ninjor, or just Alien technology to retcon them into Power Rangers' mythos.

It is unlikely that ALL 15 Sentai prior to Zyu would be used. Many used cloth designs, some had Marvel copyrights (which were relevant back in the day), too many details to count as to why Battle Fever J would never fly, Dynaman and Bioman have had English dubs. As sad as it seems, they CANNOT all be used! Only those which were unfortunately used during Super Megaforce can be dealt with: Changeman, Flashman, Maskman, Fiveman, and even Dairanger! Dynaman is a little touchy as they didn't use the forms, but Troy did hold one of the Ranger Keys as the "Legendary Battalion" during "The Wrath". The Gorenger might be justifiable if it was done as a Crossover and consciously used them as "dimension-hoppers", implying co-habitation with PR and Super Sentai Heroes, but the plot and use of those forms might require Toei's approval. One might say that the Noah-in-Jake mind-switching episode where the Gokaiger footage showed the Midorenger Key could be weaved into this, but they didn't exactly show much of the design. I wish there were others, but since PR condensed much of Gokaiger, it's dicey. Note that they consciously excised Turboranger in favor of Wild Force (save for an editing mistake). I do want more in the way of detailing on this, but we can only relegate to 5, maybe 7 team inclusions.

It is true that Masked Rider bit-off way more than it was able to chew, much less swallow down. Saban tried to cash in on the success with PR, but most of his efforts failed flat save for Beetleborgs (VR Troopers was livable to a degree). The effort would focus on the PR three-parter that debuted Masked Rider and NOT the series that followed. Toei would have to approve, but consider how "anime-based-on-an-iconic-film" theory follows: Samurai Seven got the approval of Kurosawa's family to adapt Seven Samurai even though it might not have fit everyone's fancy. If the effort got approval from both sides, then it could be used. If not, then Kamen Rider Dragon Knight might be if Saban got the rights to use that one. Adapted from Ryuki, it is not based on an Ishinomori Showa Rider and most of the Modern Riders are hotly contested for such reasons (save for the whole "Not-a-Cyborg" argument). It is unlikely to succeed, and if the matter does fail, then a Crossover with actual Kamen Rider might work if that side of the story was fleshed-out by Toei and weaved into a PR story. Ex.: The American Masked Rider from outer space lost his powers and the "dimension-hopping" RX has to help him. Not trying to step on Ishinomori's memory and legacy, but it would be nice if PR could do what Toei has tried with all the Taisen Movies.

What the fuck are you talking about.

No, Toei won't let Saban, be it Haim himself or his company, touch Kamen Rider because Shotaro Ishinomori said, to borrow a meme, "Do not talk to me, or my Riders, ever again." And since Shotaro is dead, there is no chance of reconciliation because the Japanese deeply honor their dead. It's part of why that Tsubaraya/Chaiyo debacle with Ultraman is a thing.

Or in non-Toku terms, it's like Dr. Suess' widow forbidding any more live-action movies based on his books post-Cat in the Hat.

It. Cannot. Ever. Happen. If. Saban. Is. Attacted. In. Any. Way.

Ishimori Productions are never going to let Saban adapt another Kamen Rider show. I remember Bandai of America quickly shot down the rumors of a new American Kamen Rider show. While Toei makes Kamen Rider, Ishimori Productions also co-license the series. If you want to make a new American Kamen Rider show, you would have to go through them as well.

And you'd also have to be unaffiliated with the Saban Capital Group.

That's why we were able to get Dragon Knight. No Saban connection.

You said 15. The now-official Sentai count prior to the teams adapted for MMPR (Zyuranger, Dairanger, and Kakuranger) is approximately 15. I added my two cents based on that and the fact that Pre-Zyu have "wormed" their way into Super Megaforce. Wasn't trying to be overly confusing, but I am meticulous and something of a ranter. If I misinterpreted and took things out of context, sorry.