One small example:
Lz consistently got away with short hop>double bacon>dtilt. Players would run in to punish the end lag of bacon, and get hit by dtilt. This happened quite a few times, to quite a few different players.
Understandably, that is only one example, but it just goes to show that players were failing to adapt and failing to recognize something that they were getting hit by. I get that it's hard, because he uses bacon in a very safe way, but I'm surprised more players didn't run up shield, or dash in WD back, or do something to bait the dtilt.
I think G&W is a great character, and I think Lz is a great player. I don't think his opponents were playing the MU particularly well, and they suffered for that. As a result of that, I think that all of the salt about G&W is misplaced. Sure, he has very safe frame data, he hits very hard, he lives very long. But I think the counter play can be improved to a significant degree.
I get that a certain character can be frustrating, confusing, difficult to deal with, etc. But, this is the game in its final form. You need to find something that works. Do something differently. If all else fails, try a new character. I absolutely despise the Wario MU with Ness. But, if Jose V. can beat Sosa, then there has to be more that I could be doing to improve in the MU. Just another way of thinking about things.