Bort
If you were comparing Mr. Freeze episodes and nothing else, I'd agree that the original series had the better story. But comparing series to series ... ? As with SNL, people tend to insist that the early episodes were absolute brilliance and forget they included their fair share of dogpoop too. There were a lot of "Batman Beyond" episodes that didn't do much for me, but not one of them was as offensively stupid as, say, the old BTAS with the orphans and the Fagin-like character in the sewers with his pet alligators. Try watching BTAS again with fresh eyes, you'll find that there was bad mixed in with the good as they fine-tuned the show.

Remember how Batman defeated Mr. Freeze in that first episode? That's right, with chicken soup -- "the only way to stop a cold". You didn't want to remember that, but I made you.