The problem with Zelda II is that it is not a bad game, you see. It's actually great. But all things in consideration, it might be the weakest Zelda game entry, as the Zelda franchise itself.
What you people are not seeing is that when there were only Zelda 1 and Zelda II, you could hardly say Zelda II was the worst Zelda. Zelda wasn't an established franchise yet, so it was a matter of preference. The thing is, the franchise went on with Zelda 1 style. Hence why Zelda II became outdated.