>>24736521Gen IV made babies actually relevant. Before then they were a pointless gimmick meant for marketing. Gen IV gave them a purpose (instead of flat-out giving you a Mr. Mime, they send Mime Jr. at you so you get the satisfaction of raising and evolving it that you wouldn't get from just using plain old Mr. Mime). In other words, they make babies work by having them wild encounters instead of something you can only get by breeding after you already have the mon you want.
What made the legendary encounter lackluster was the fact that it made no sense. In Gen 3 Kyogre floods the world, Groudon dries it out. They are a threat, essentially. In Gen IV, Palkia/Dialga flood the sky with generic multicolored rays that do nothing. If they'd shown Dialga reversing time or Palkia reconfiguring space, that'd be one thing, but they totally fail in this regard. Furthermore, they do a lot of telling as opposed to showing. When the red chain binding Palkia/Dialga snaps, you discover this fact through dialogue -- you're never actually shown a red chain. Plus Cyrus loses control over the legendaries before he can do anything with them. When you're fighting him, there's no tension -- you're not wresting control over the legendaries back or saving the world, you're literally just trying to calm Cyrus down because he's feeling anger for the first time in his life.