The ball and the players can be moving around as drastic as you want, but both their movement patterns are predictable.
*The ball because when it's in motion, it's usually airborne, constantly bouncing off surfaces, and as it bounces along the ground, it's horizontal movement progressively gets slower to the point where it becomes easier for players to control(Unless it bounces off a slope at certain angles, based on the ball's trajectory).
*The players because in a practical game, they will always be moving in accordance to where the ball is. There are only two main movement patterns of which to employ, in terms of the ball interaction. Offence and defence.
Offence is usually just players following the ball; trying to keep it on track with the opposition's goal, while defence is more of intercepting the ball, trying to cease the opposition's progress, and clearing the ball away from their own goal. (So usually, they'd either try to get AHEAD of the ball and anticipate it's movement in order to clear it away, OR simply knock the ball off-course and make it hard for the opposition to progress.)
At those high speeds, distinguishing it from a player is the most important thing
I don't think the pace of the game is as fast as you might be implying. Don't get me wrong, it's fairly fast-paced, but not to the point where players can't keep up with it. If that was really the case, wouldn't that be more of a problem to do with the game mechanics or the player count(Which I'm about to go over)?
The issue with the ball specifically is that it's one of (n+1) objects moving around at a frantic pace, where n is the number of players.
Ok, now this begs the question; do you guys have official max player caps dependent on the map size in mind at this point?
I get where you're coming from here; in that maintaining focus on the ball up close while there's a lot of players moving around alongside it might be difficult, so where exactly do you guys draw the line on max players?
Think about it; imagine a small map with 32 active players. It'd be complete chaos. This is where the problem can be either the player count(In accordance to overall map size), the ball not being distinct enough, or a mix of both. When there are too many players moving around in a map for you to maintain focus on the ball, how exactly do you determine where the problem really lies?
Could the level just simply be too small for the player count? Does the ball not stand out in any shape or form from the players, in terms of overall appearance? Or do both of these seem to be the case? That's the kind of thing you'd have to truly think about to come to a proper conclusion.
Now here in this case, the ball is going to be fullbright. The players are darker than normal. The level is...Hmm, hard to say actually. Medium? Large maybe? =S Either way, I'm pretty sure focusing on the ball in the midst of action, where there's a balanced amount of players would be a cakewalk, since the main thing you're interacting with will be fairly bright and have a good amount of overall contrast to the dark red players.
but there might be a player close by that confuses you. THAT'S the issue.
How would that happen in this case though? Again, look at the fullbright magma ball sprite again, then look at any of the characters sprites within the level. Are you trying to tell me that between a fullbright lava ball and dark red characters, that it would be incredibly difficult to tell the difference not just up close, but in motion? Considering how dark the map is, if one of those actively moving things are as bright as all hell, it's gonna stand out. The bright yellow outline of the ball(which is very noticeable up close) and the fact that the main colours are fairly mixed on the sprite make all the difference too.( Doesn't help that the public version has a ball that isn't fullbright, and that's my fault really. Even so, there are screenshots of the fullbright ball in my previous post. Regardless of where this discussion goes, the ball is definitely gonna be fullbright in the update, so judge it based on that instead of something that's going to be irrelevant.).
Now, as for the character's spin/jump frames; that's usually a dominant red/blue colour. I only mention those frames, as that's the only thing close in shape to the ball, of which I can see where the mix-up may potentially come in. However in this case, you'd probably see the magma ball miles better than you would see the dark red characters, since it's gonna be fullbright(and as a result, have better contrast with the characters).
Even when the ball and players are in motion, you'd pretty much have to either:
*Be behind a wall
*Have way too many active players around the ball
*Be far enough that you can't tell the difference between the ball and players(Which I'll go over)
for you to lose sight of the ball itself.
If you're too far that you can't tell the difference between the ball and a player(even with the crosshair and the difference in brightness assisting you), then you should be moving close enough to where that isn't a problem. Even if you wanna play the rebel and choose not to, why does it matter if you can't make the distinction at that range? You're not even close enough to interact with the ball, so even if there's some slight confusion from a distance, what difference will it make? You may as well just rely on the crosshair if you REALLY wanna keep track of it from that kind of range. On that note, have another screenshot:
https://www.dropbox.com/s/vhs20q4drlvm9ri/srb20043.png?dl=0
You can't honestly tell me that from this distance, you can see the red Sonic MILES better than the fullbright lava ball(and the ball doesn't even have the crosshair over it, of which would be of relevance from this distance.). Clearly there's not a problem with distinction between the ball and players, because the ball's way brighter in comparison.