It's not really an excuse, there are just a lot of games that were never built to support a metagame in the first place, so whether or not it can actually support a competitive environment is completely random.
Basically, if you go into brawl expecting depth of mechanics, you're going to be severely disappointed. If you come into it expecting to have fun fighting as nintendo characters, you're going to like it fine. In fact you might actually like it better than melee depending on what you value more, as the subspace emissary is currently, and will probably continue to be the most fleshed out single player option in any smash bros. game, as well as a good character roster (some of which, like snake, probably aren't coming back.)