There's no point getting mad about changes George Lucas makes to the original Star Wars films anymore. They're amorphous blobs more than films at this point, and have been since Lucas started seriously tinkering with them back in 1997. And that's okay! The original versions of the films still exist, so you can always cling to that, but the new ones are actually pretty fascinating, if for no other reason than Lucas makes some very strange, subtle changes. We all know (and mostly agree) how weird it was to reverse the Han/Greedo scene (the infamous "Han Shot First!" battle cry of internet nerds for the past 15 years), but there were a lot of changes made, some of which have some seriously questionable logic behind them, and these are some of the most baffling.
But the Empire is not only technologically advanced, they are the MOST technologically advanced organization in the galaxy. They have a laser that blows up planets. They can have their giant Star Destroyers travel at light speed with no issue. But when they're looking for droids on a desert planet, they choose to travel by giant iguana? You have to feed and care for these giant, unwieldy animals that are difficult to control. Even a poor farmboy has a landspeeder. Why wouldn't they use one too? Odds are they have ones that are way better than Luke's, and would probably have tools to help find droids that would not be susceptible to bearded old guys waving their hands. If one or two Stormtroopers were using dewbacks it would be okay (maybe their landspeeder broke down or they were being punished for another terrible day at the shooting range), but the idea of this many Stormtroopers riding fat, slow iguanas is a little weird.