Much like Snake uses his grenades to limit his opponent's options, throwing SPs up or down makes what are essentially "danger zones", which discourage passage. One of the biggest reasons that Snake has been so successful as a character is because of his versatile stage control abilities, particularly his grenades. Snake's grenades and our SPs are very [similar].
[The mian] way [in my mind] to do this would be to throw your SPs up. When suit pieces are up in the air, they function similarly to one of Snake's shield-dropped grenades: A hit box will appear in the spot you initiated the stage-control mechanism in a matter of seconds. Same concept: Stage control. But another difference is that they won't have a chance to throw them back until the hitbox reaches them, which takes time and effort to do correctly without getting hurt, and if you keep the pressure up, that most likely won't happen.
[Many people would see an obvious flaw in using the SPs like snakes grenades, in that doing this would not work at all.] It's not that the SPs don't work as a stage control game as well as Snake's grenades, it's just that they work differently and therefore would have to be used differently for stage control, but I do believe we can get the same or at least a similar advantage from our pieces if we use them right.
I'll start us off with a few of my ideas. I know people are flawed, and I kind of came up with these fairly quickly, so if you see any flaws, feel free to explain them and place your own input.
The idea behind this is that we would start our games much like Snakes play all the time: Use stage control to not only do damage, but force mistakes to punish. Glide tossing up would be an amazing thing here, allowing you to throw one piece up where you want, and glide over to where another is coming back down. It would make a good mind game to glide-toss a piece up, and then jump into the air, grab one on its way down that the opponent was keeping track of so it wouldn’t hit them, and then throw it down at them, or throw it down somewhere else to throw them off. Similarly, if you don't like where one of your pieces is in the air, or maybe you need another piece to use, just jump up and get it. Yes, this again. In theory, it's pretty safe if you know what you're doing. Down throw makes an amazing Dair. The problem is often what happens if your other pieces are on the ground when this happens. Your opponent could go right for them. This is why you constantly want your pieces in the air! I imagine sort of a stage-wide SP juggling operation. You would utilize your superior jumping ability and glide tossing to juggle your SPs all around the field as stage control, jumping up and grabbing pieces you’d like to re-position elsewhere or throw, maybe mind gaming the opponent with this on a regular basis, and in between these actions fighting your opponent that is in constant annoyance and danger of falling hunks of metal armor. Maybe even throw some flip-stools in there every blue moon when you need to move across the stage quickly but don’t have a piece in hand.
SP strategies would probably vary with stages and characters. For example, the technique I just described would probably work [well] on final destination, because jumping up to grab a piece would not result in ZSS landing on a platform where she would be vulnerable, and pieces would come straight to the ground where they are needed, but the technique would be very annoying to keep up on [rainbow cruise] because of all the [wierd moving]platforms, for the converse reasons. I imagine this working very well against snake, setting off his grenades and mines, as well as punishing and destroying many of his other attempts at stage control. As we move into bad characters for this strategy, irony ensues, because the strategy that works so well on FD would probably not work so well against Falco at all because of the reflector, and most of all, the lasers that aren’t going to be stopped by SPs, destroying the defensive aspect of our strategy. But this is why we need to work on this! I imagine dozens of variations of strategies that work from stage to stage and character to character, and that’s something we should really work on. Are you starting to understand why I find this so exciting?
I want you now to start thinking about different characters, and different stages. Experiment in practice mode. ... Remember, this is a discussion thread, not a lesson thread: I'm just trying to get your minds going. Look for things I may not have mention yet: I haven't brought out JCT's (Jump-Canceled-Throws) at all yet. What could we do with those? I hope by now I've helped you realize how unexplored this section of her metagame really is, and I want you to start exploring yourself.