Definitively easier. The whole of B/X Basic was 64-pages complete with specific procedures to follow in most cases. Whereas 5E is in excess of 988 pages without much guidance at all on how to run the game...which is kinda what this thread is about. The lack of guidance on how to DM and onboarding new DMs. If 5E were that easy to learn to run for a newb DM, this thread wouldn't exist.
Compared to 5E? Running AD&D is a breeze. The organization of the books is terrible. That's absolutely true. But the books are also filled to the brim with info, guidance, charts, tables, procedures, etc. And 2E? Even easier because the books were better written and better organized...plus there was an entire line of books specifically about various DM-focused campaign needs. Some notable books include: Campaign Sourcebook and Catacomb Guide, Castle Guide, Castle Sites, City Sites, Complete Book of Villains, Country Sites, Creative Campaigning, Dungeon Builder's Guidebook, Monster Mythology, Of Ships and the Sea, Rogue's Gallery, Sages & Specialists, and the World Builder's Guidebook. Not to mention all the great settings and the historical-period books. Chances are if you wanted to run any kind of game in 2E there was a book for that.
Mine would be, in order: OD&D, B/X, BECMI, RC, 2E, AD&D, 4E, and 5E. This is basically in order of publication because as time goes on the rules become more complicated and bloated. The only reason AD&D is "out of order" is because 2E is a cleanup of AD&D with wildly more support. I never touched 3E. Whatever people may think of 4E, it was a focused game that did what it was designed to do well.
Exactly.
Both 4E DMGs are fantastic. They're miles ahead of the 5E DMG. It's not even close.