DISCLAIMER: I'm going to be talking from my experience as an unlimited player, though most of my remarks still apply to OS in theory.
These game modes have been around since forever, but they have enormous flaws which in part explain that they are much less played than Touch Down (and perhaps Death Match).
The capture points don't matter. People are just exchanging 7 points (capture + point pick ups generated from the capture) back and forth but in the end those capture points only create a differential of 21 (7*3) points, which is underwhelming considering that team scores often go up to 300 points (although that figure is inflated by the fact that playing the capture game accelerates the acquisition of points by both teams). What matters is killing enemies and getting point pick ups (which you can do from enemy bases).
But let's consider that, hypothetically, you do not want to give those 21 points up. In that case, the only captures that matter are the first and the last. In other words, once a point is captured from being blank, the only time you want to capture it back is during the last 30 or so seconds of the timer.
I mean, it's not an issue for me, I like playing death match with ammo/SP/HP pick ups, but it fails to be its own thing.
Fixing it would be easy, give an advantage to teams that can keep bases, like a buff depending on which base you have or just a point every X second or something.
-Cannot start a match while there is less than 4 players: It makes no sense, how is it an issue to start at 1v1 in captain? It's a big deal too, because finding 3 players to play a game that hasn't started yet and in an underplayed mode is near impossible unless you ask in your friends list or something.
-numerical advantage: Sitting is impossible in Captain (since you have to die first and if you offer your life you're giving the enemy team an advantage because of the compensation). The compensation (aka more HP when the enemy team starts with more captains) is nowhere near enough in most cases, since having the numerical advantage in S4 league is worth way more than a few additional HP.
-It concerns mostly unlimited, but crowd control (mostly MKII bomb and bind) and healing are way too strong, due to the time to kill being higher than normal.
The fixes for this one are obvious. Make it so you can start at 1v1, rework the compensation (more damage, SP, ammo?), make special rules for Captain that forbid healing and crowd control.
-This gamemode is flawed since it relies on the kill credit system which is flawed in S4. The last hit is worth 2 points, and anything before that is worth 1 point or less, even if you deal 99% of a player's life.
-It's even worse when you consider the target system: the last hitter gets 5 points, and aside from that still 1 point at most.
-But the biggest issue is that the game gravitates around getting those 5 points (5 points is a lot), and the person in first place cannot have those 5 points (and also has their position revealed to everybody). It means that when there are several good players, the first place changes constantly, and in the end it feels like whoever wins just got lucky that they happened to be in first place at that particular moment. Basically, it's like if people had pity 5 in touch down whenever they were down by 1 touch down or lost in points.
-It also creates situations here the best play is to, for example, let yourself get finished off by an amateur because you don't want to let someone more dangerous get the 5 points, or choose to not kill anybody when nearing first place because you don't want to be in first place, which isn't how games should be decided.
This game mode cannot be fixed completely until points are given more adequately, but removing the 5 points on killing the first place would be a start (I like the target though, it makes it clear where you'll find people to kill)
-As long as the Chaser cannot run out of HP, the chases are always going to be one sided. In gun matches, unless enough people bring rail guns, the Chaser is guaranteed to kill everybody if they play well enough no matter if they are against better player. The Chaser needs a nerf, at least in unlimited.
-We all know rail guns in Chaser are an issue, even though I like that it provides the chased with the means to defend themselves but hitting that huge reaper thing is way too easy, and it doesn't help the user in getting better aim. I do not think any gun or sword should be able to damage the Chaser by damaging the reaper thing.
-Once again, the target system and bonus points are what ruins the mode for me. When you're first, it's extremely unlikely that you survive if the Chaser has any idea what they're doing, and honestly very often it's even detrimental to try to struggle and waste the chaser's time since you're also buying time for everyone else on your team, everyone else you're competing with. But more than a matter of points or winning, it's a matter of fun, as the first place you spend most of your time watching others play because you got hit twice in the head by submachine guns during the first 20 seconds of a round and it's enough to kill you.
-The worst part is, not only does the phenomenon I described for Battle Royal still applies, there is another element of randomness specific to chaser, and that is, the order of the chasers. Because of how much point being the Chaser represents (at least in unlimited), whoever gets to be the Chaser last is vastly advantaged, because he gets a lot of points without being penalized for having a lot of points.
Sorry if it wasn't very interesting, it's just that all of this seems obvious to me and I thought that somebody had to point it out, though I have no trust it's going to change anything.
I am of course open to criticism and if I said something that is not factually right or made a leap of logic somewhere, you are welcome to point it out.