I think the best way to make the technology seem less advanced is just making the whole look more Arthurian mixed with some technology, some of my favorite visuals in this era during the games were all the Jedi and Sith temples.
In A New Hope, Obi-Wan mentions the lightsabers being used for a more "civilized" era, and that they weren't as random as a blaster, pretty similar to how certain Samurai didn't like firepower (even though according to most history records, they used bow and arrow more often than swords). So my proposal would be to make blasters less common, if the main saga's period is like the wild west, then this era should be more like an age of knights. Taking this into account, force wilders wouldn't be as fast and not all of them would be able to deflect gun blasts.
Theoreticaly, the ships would be as fast either, in the main saga we all know that they only take a few hours to days in order to go from a certain planet to another, it would be interesting to see how different the dynamic would be if it took them months to even years between locations, it would make wars goo differently, pretty much how wars used to be waged 1000 years ago. Would also explain why the original Jedi vs Sith war took so long, without having it look "bigger and more epic" than the wars shoun in the main saga.
I hink there are other littles ways to make it clear that technology isn't as advanced in this time, the thing with keeping the technology static in the SW unvierse is that in the original saga, things seem to advance a bit technologicaly as time goes by. Isn't even one of the upcoming Rebels episodes apparently dealing with the appearance of one of the ships that would be used in the original trilogy? The Clone Wars show also had some military advancements done during th war.
As for how this period is explored,i think that keeping it as part of the Anthology series could be a bit limiting, if Disney sees a major success in the brand, then it's doubtful that they would stop a bit after Episode IX, instead of going right to Episode X, i think they could go to this period and try making a Knights of the Old Republic Trilogy.
This era would open up a whole new can of worms, and could even spin off a whole set of stories dealing with the original Jedi vs Sith conflict. If Star Wars centers around Jedi vs Sith, the whole story would pretty much be divided into 2 parts, the first one being more like a "period of knights", while the second one would be the Skywalker saga which is shoun in the main Episodes, with the 1000 years of peace in between being a sort of timeskip between both eras.