Originally posted by Octorox:
"Oh come on. If things could just form bubble shields around themselves why doesn't every unit have one? Why don't the stormtroopers have little transformer walkers they can deploy from cubes. OT technology is clunky and practical while PT tech is crazy science fiction stuff that doesn't seem like it could possibly be engineered."
You can't say that because a piece of technology wasn't present in the OT automatically means that it didn't exist.
In-Universe, the tech wasn't showcased simply because no one used it on screen.
In the real world it wasn't showcased either because no one thought of it, or didn't have the resources to produce the effect at the time. When the PT came around someone said "Hey, now we have an opportunity to use this stuff, and there's no real reason why it should conflict with OT because we can just say that no one used it on screen in those films" which is a perfectly reasonable explanation. I'll say it again: Artistic License.
Also, the abilities that you're referencing were exclusive to battle droids, more specifically battle droids in battle. And, I don't mean minor skirmishes like those in Cloud City or on the Death Star. I mean full fledged, planned out military campaigns with two armies going against each other. Even if the Droidekas in the PT had been replaced with flesh and blood soldiers, technology like the bubble shield is the type of military equipment you would only bring out during a preplanned military campaign like D-Day or the Battle of Geonosis. The only instance like this the comes up in the OT is the Battle of Hoth and, like I said before, we just don't see enough of the Snow Troopers in battle to discern whether or not they had brought technology along the lines of bubble shields with them.
I don't think you can count the Battle of Endor the campaign category because the rebels on the ground were part of a spy convoy, only enough to fit in the Tiderium, thus not constituting a full blown military campaign. The stormtroopers that ambushed them knew that it would be many against few, and I don't think would have deemed it necessary to bring along such tech. Of course the real life reason is that Lucasfilm just didn't put that type of stuff in there, and there is not problem with that.
You also have to think about what cultures were utilizing what tech in the PT. In the case of the Gungans, their battle shield seemed to be a device that was culturally exclusive to them. They are the type of culture - at least base on what was present in TPM - that forces their enemies to come to them so they can destroy them with short range weaponry. How many Gungans do you remember seeing in the OT. On top of that, let us not forget Nute Gunray's line "[The resistance] appears to be made up of primitives," which could indicate that the shield technology they were utilizing was on the verge of being obsolete.
EDIT: Isn't "clunky and practical" a bit of a misnomer?