"...some of the most significant changes that have occured during the past 30 years in reloading?? "
Components aside, as a loader of some 45+ years I can say the most significant chages in loading has been the proliferation of excellant measurement tools at affordable prices.
Machinest's micrometers, dial indicators and calipers were expensive and therefore rare on loading benches thirty years ago. Very, very few of us had chronographs. Concentricity gages and easy to use case shoulder length tools and seating depth to the ogive tools were yet to be developed. Without them, we cound not accurately measure what we were doing so it was almost impossible for the common man to make precision ammo with any consistancy. Now it's so easy as to be almost without thought!
Other neat toys such as tumblers, neck turners, primer pocket debur and uniforming reamers, micrometer seating die heads, digital powder dumpsters, progressive and auto-indexing presses, etc, are nice but they all pale in impact on our activity compaired to today's tools to simply and accurately measure things.