Yeah, the Mirrans weren't exactly the brightest planar denizens in the multiverse

Oh! Sidenote: I forget who bounced this idea around before (I think Barinellos?) but one problem between the two Mirrodin sets--the rapid change in how the goblins looked--miiiight be explained by the influence of... The Mirari! [bum bum bum!] It was lost when Slobad was killed by panicked goblins. Despite being lost, it might have worked its charms on the goblins that still lived in that area, resulting in the more feral looking creatures we get in Scars.

It's not a perfect patch over an annoying retcon, but it's a start.

Actually, it WAS explicitly stated in the Time Spiral player's guide what the Time Rifts screwed up.
Yeah, that was mine. Headcanon go!

Mirari mutations + the faster reproduction cycle of goblins = bat goblins

The problem with Mirrodin is that the second book in the first cycle is a blur, with the exception of a talking wolf. With the Scars block, there was too much time put into making the Phyrexians new and exciting. The Mirrans didn't get much in the way of development. Also, Wintermute's novel didn't do much with the Praetors or the Mirrans. I wanted a look at how the Phyrexians were screwing with the Mirrans on a psychological level. The only good things in there were Venser's addiction to...what was it? Blinkmoth serum, and Elspeth's past. Lack of decent characterization and the world's distinct flavor contributed to a bland reading experience.

The idea that Memnarch was protecting Mirrodin is cool, too.

My problem with Mirrodin was there was always a dissonance for me between what I knew about the different Mirran cultures and the cards. It was the "metal world" and that translated into people having metal growing out of their bodies and the landscape being metal but they were otherwise pretty low-tech. People talk about Mirrodin being the closest to science fiction but Ravnica and Innistrad have much higher levels of technology, so I was never sure where the sophisticated artifacts were coming from.

I stand corrected! I knew it explained that they helped Memnarch shut the plane out from the rest of Dominia but forgot that it actually did explain the accelerated timeline, too. For some reason I thought that was a patch we came up with.

It still leaves us without a patch between the Barinellos and Brady post-Mending timelines though

I think I finally have an idea of how I would have written it.

First, although it seems like Otaria made it out of the Phyrexian invasion mostly unscathed, the Phyrexians had in fact become aware of the continent and were planning to launch an offence against it at the end of the war. This plan never had a chance to come to fruition, but Phyrexian agents had managed to smuggle several barrels of Glistening Oil there before the war was lost and the plan abandoned. When the Mirari came to Otaria, it landed in this forgotten Oil storage. Trying to fulfill its purpose as an observing probe, the Mirari absorbed the Oil into itself, causing a terrible malfunction, which threw the entire continent into turmoil. This explains both why the probe malfunctioned and how it could have such corrupting power.

Then, when Karn turns the probe into Memnarch, it further changes the nature of the Oil, and in the process, some of it attaches to Karn. Now Memnarch is constantly trying to fight off the corrupting influence of the Oil within him, desperately holding on to Karn's vision of purity and peace. However, knowing that he himself is impure is driving him mad. He tries to stave off the madness by turning the plane into an image of order, where each thing and each being is in its own place, but still the corruption eats him from the inside. He knows that he needs Karn in order to achieve the purity he longs for, and goes to extreme lengths to find him. During this time, he can feel a planeswalker trying to enter the plane, but he can also feel that the walker is carrying the same corruption he is fighting, so he pushes him away.

Finally, when Karn manages to get through, and turns Memnarch back into the Mirari, it again causes the Oil to leak. But now it has been completely changed through Memnarch's mad power. It has been infused not only with his power to warp entire landscapes, but also by his image of how the world should look. Thus, as it starts to change Mirrodin, it does so in the image of five separate factions, just as Memnarch always envisioned the plane.

I +1'd that. You all should too.

Awesome indeed.

Too bad I have neither the time nor the commitment to turn this into a full series of alternate history novels.