An interesting, and im my opinion good, thing about smash is that a better player can usually win with more than half the cast. Everyone has had that moment where they play someone for the first time, and you naturally bust out your main. What do you do if you win, rather convincingly? Unless you are hardcore training, or extremely dedicated to your main, often you will switch to another character. Smash rewards lots of things, and many of those things are consistent across the cast. If you can force someone to roll out and punish the roll, you will do well with any character that can do both of those things. Of course, the best choice might be the character that can force the situation the most often, or the character that can punish the hardest when the situation comes up.
The frustrating thing about the current meta, is that it is dominated by a jack-of-all-trades speedster. Shiek is probably the best at forcing the roll, due to her oppressiveness, and an optimal shiek will punish the roll among the hardest in the game, given a skilled player. This is a crude example, but kind of shows what I am trying to get at.
The idea of her being dominant in many attributes can be summed up with the MU that many mid-tiers face against her. Ask a greninja player why he has trouble with shiek, or where he thinks he can edge the matchup in his favor, and the problem becomes evident: 'She is better at everything'. Of course, this isn't true in the simplest sense. Greninja's fair does more damage, and has more range. But, trying to formulate a gameplan around that? Then you see that the Shiek player has a better tool to contest you with, than you have to fight her with.
I'll speak more about the character I know, since I don't have much more input on greninja from a players' point of view. I've had some great games against Shiek. It can be a rewarding and fun match where the character with better CQC tries to fight through a wall of projectiles, using her superior burst movement and frame data to make as much from that when she gets in as she can. She has better kill setups and gimps, megaman has better raw kill power throughout his moveset. But, upon seeking a reprieve from the zoning onslaugt, the shiek throws a wayward needle. It hits. After a few of these, she realizes that she doesn't have a need to do any of the above matchup, instead just force the approach and shut it down with her better options.
And again and again. Everyone has trouble with something. A 'balanced' top tier is a nightmare for various reasons. Of course, the best answer is to outplay the player, and that is possible and reasonable at most levels.
This kind of became a rant, more than I wanted it to, so I will get at what I was going for with the next questions. These aren't trying to lead to a point, just legitimate questions I have in my quest to beat the oppressive queen.
What type of playstyle does Shiek struggle with the most? What type of player do we see have the most success against Shiek? Are there any (non shiek) players who think she has a losing MU, if so whom, and why?
I found Sol's little mac vs shiek analysis video incredibly interesting, when he says shiek is a linear character. I find her not to be, but from the eyes of a great Mac she is. Is this due to the way Mac plays his neutral/footsies? She has options, but they boil down to the same thing against Mac, why does he care if she is spacing fair into ftilt vs dtilt vs jab vs grab, pivot Ftilt beats it all!
I wonder if she will prove to have losing MUs in the end, and we are just pessimistic because the best players choose shiek, and she looks even more dominant. Perhaps a smash64 approach will help, with powerful SDI to negate 'guaranteed' combos.
This post is now huge against my intentions, since I like typing far too much.