I don't quite understand, I started in SP first and from there it helped me improve my skills in MP.
I learned what the joints did in single player with out having to worry about what my opponent is going to do. Then transitioned to MP and all I really had to improve was decision making and mechanics that changed from SP to MP.
But you saying that SP players put greater importance on effective movement than MP is just wrong I feel.
So considering SP players have more time they can see more possibilities and therefore put greater importance on effective movement.
That is false way of thinking it. MP players only consider the optimal movement, disregarding any style (usually), since there is no time to tweak everything. Of course the movement in SP will be better, who's arguing against that? But the focus isn't effective movement, as much as in MP. There is style etc involved.
I don't understand what that argument is trying to prove? I can say with certainty that the top players regard every joint when it comes to movement.
In SP you can go back and fix any mistakes or make something better... in MP you either don't make mistakes, or you learn to work around them... SP is goof for learning the game but eventually the player will want to nice to MP. A lot of the best replays are made in MP as well... For example, check out Obey's clan video... knowing them I know they didn't stage that but rather fought and would make it realistic (such as a rule if up get punched you have to get knocked back a little) and MP challenges your ability to work around a player... SP the creativity is definately a big part, but once you get the idea, you can spend however long to make it. In MP, you have to decide what kind of fight you are going to do (ie shovel, grapple, etc.) and have a few seconds to execute your move. You also have to be able to compensate for your opponent's movements where as in SP you can just make Uke do as you wish.
SP Is good for learning and for testing.
MP Is good for challenge and for getting ideas possibly.
BOTH would be perfect for the ultimate player and/or repay maker.
Both are really different.
In Mp there's a bunch of mods, you can be good at Aikido but you can suck at Wushu. Also there's a lot of people, you can never know if you're the best or not. Getting in Mp isn't easy, you have to play a lot of matches to get at least a bit of knowledge of what you're doing.
In Sp, each player has his own style, there's a lot of ways to play it and each one requires so much knowledge (madmans, tricking, parkour, solo-spar).
The thing is, both things aren't really comparable, they are different.