I grew up in an era where WDW had free-roaming characters and no meets (that I recall). It was kind of exciting to turn a corner and be surprised by an unexpected character, but I also don't recall ever actually interacting with many of them because they were surrounded by other kids.
Fast forward to today when I can pick which character(s) to meet, and interact with them in an orderly fashion and in a setting that makes perfect sense. I feel like there are more characters in the parks today than there ever were and the waits for most of them aren't that long.
Having said that, I'd looooove to see some organized "free-roaming" meets with groups of characters (like the Alice example above).
My biggest point would be this though: WDW doesn't necessarily need to "learn" anything from DL -- the same company controls both parks. If anything, Disney needs to spread the wealth a bit. I get tired of hearing "oh DL is better because...". Well, it is better in some respect and not others. They're both great, but it does feel like DL always gets a little bit more polish on everything they produce for it. They get the latest bells and whistles. And while some of that may be due to the fact that DL is right in their backyard, WDW is close enough that we shouldn't even be having this conversation.