Excellent thread!
I'm new here, and a Mario fan. Hi!
I'm returning to handheld gaming after a LONG hiatus.
I wasn't aware that any changes at all had been made in these classic releases!
My wife and I stormed the 1st SNES Mario World back when we were first dating.
(SNES is still hooked up downstairs)

I just bought a GBA SP NES Edition, and simply picked up where I left off when I gave away my original GB 14 years ago.
That's right, I'm working through SuperMarioLand 3 - Wario Land!
I was thinking I would simply play each one in the series through, working my way up to the GBA releases.
Just picked up SuperMario Advance 1 on Ebay, and look forward to re-visiting SuperMArio World again too.