Newer models sometimes have better dip tubes or different lining that helps a bit, but nothing replaces just getting the gunk out once a year.
You nailed it there. All the fancy features in the world can’t outdo a good old-fashioned flush. I manage a few older properties, and let me tell you, if you skip a year or two, the inside of those tanks starts to look like a snow globe full of gravel. “Popcorn” noises are almost always sediment getting cooked on the bottom—each pop is a little water bubble fighting its way through a layer of crud.
I’ve tried powered flush kits and, honestly, I’m not convinced they’re worth the money. They might blast out a bit more, but if you haven’t kept up with annual flushing, the sediment just clumps up and you’re still stuck draining it by hand. Gravity works fine if you do it regularly.
Pressure relief valve test is a must. I had one seize up on an old rental and it turned into a mini geyser when the tank finally went. Not fun, and not cheap to fix. Skipping that step is asking for trouble, in my experience.