I completely agree, though I suppose it's alot easier for me to than others, considering I play Marth and Snake and other versatile characters. And the stages are really not that bad; it truthfully is not unreasonable to expect people to not be getting hit by cars on PTAD. Stage knowledge and adaptation deserve to be skills that players are tested of, just like other universal skills.
I'm not against there being no universal LGL, but I do think MK is very much a problem here. I don't know the exact frame data, but I believe it's impractical to expect players to beat MK when he's planking as perfectly as possible. If the MK has the lead, I think it's safe to expect that the match is over if nothing is preventing the MK from doing everything possible to avoid being hit. The match's fate shouldn't be sealed the instant MK has the lead.
But I dunno the frame data. :|
If it is possible to hit MK, the fact remains that an error will put you farther behind.