The misinformation here reeks.
Brawl has a ledge grab limit because of Meta Knight, very few other characters can abuse planking like MK can. The characters that could have decent planking game have other bad things going for them to where it would even out. There is literally no other reason for the LGL.
As for the Melee statement you made, that is also false. Camping is still a tactic and people can still do it. What do you call what M2K does on the ledge with Sheik? Camping. Samus is a character that can make good use of camping with the current stage list due to all but 1 having platforms. Fox and Falco can laser camp still, the especially want to do it when going against Jiggs. Hell the stage PS1 promotes camping. Camping still exists in Melee, saying otherwise is ridiculous. Your also going under the notion that camping is inherently banned, when it isn't.
As for the whole L-cancel diabolical. I use to be in the auto L-cancel camp, but that would end up giving an unfair advantage to the heavier characters. I would rather see L-canceled expanded upon instead. Perhaps make it specific. Instead of having every aerial be able to make use of it, why not instead have only the aerials with a noticeable landing lag, like Peach's Fair, Brawl Falco's Fair, most Dairs, ect... and instead only have the lag reduce to a lag that is just a tiny bit less than a "normal" aerial. This way it keeps it all even and tried not to favor on weight set of characters to much and makes the laggy moves require more work to be put in for them.