The difference is that now he’s actually trying to sound different.
“It was a conscious choice,” Morrison says. “I thought, every now and then he hit some tonal qualities where, hey, he has been scarred. He has been affected internally, as well. So without sounding too false I wanted to bring a little gravel in there to give it a bit of timbre.”
While for the 04SE they called him on the phone and had him record dialog at his house with no thought or planning on his part, as far as I can tell. So he just did Jango. I so wish he’d thought to make Boba sound different than Jango back in 2004.
I guess my main point is in The Mandalorian Fett sounds exactly like he did in the 1980 version, so now I really don’t see the point of the ESB 04 voice change if Fett’s voice changed over time anyway. I absolutely hate the 04 voice change.