I don't think slavery has been an issue in any MegaMan game, save possibly 9. Prejudice, certainly, there's tons of that in Zero and in X4. But the X-series as a whole is more about survival of the fittest. The philosophy behind Mavericks isn't to "liberate" themselves, but rather that the "inferior" humans are limiting their growth and should thus be annihilated.
Maybe the point of the series was to show how NOT to rebel against slavery.
X' final series is X10, (console: PS1) (^^)
This may not be as ancient, but I'm sure we've all heard someone claim that the X in MegaMan X is actually 10 as a Roman numeral, so the original series ends with the 9th game. Bonus points if they claim that the ninth game was MegaMan and Bass. Now that MegaMan 9 has put the latter myth to rest, we need MegaMan 10 to come out to take care of the former. (And what's with this attitude that one series needs to be ended arbitrarily in order to "kick off" another one?)
There is nothing broken about MM3's weakness ring. It's just actually two rings. And the GB games generally do not honor previous weaknesses, in part because they mish-mash bosses from two NES games.
But the GB games do honor previous weaknesses. It's just that they have to make up new ones in order to fill in the broken rings. By "broken", I mean that some bosses from the original game's weakness ring were missing, so the GB game had to add a weakness of the boss at the beginning of the broken ring to the weapon at the end of it. Let me show you:
World 1Cut -> Elec -> Ice -> Fire -> Cut
GutsMan doesn't appear, but Fire Storm was already CutMan's secondary weakness anyway, so this makes sense.
Bubble -> Heat -> Flash -> Quick -> Bubble
This is pretty much what the weaknesses would end up being if you removed the other four MM2 robots, but this time QuickMan actually seems to be a little weaker to
uncharged Atomic Fire than FlashMan, and FlashMan's also weak to Ice Slasher, so that can mix things up a little.
World 2Clash -> Metal -> Wood -> Air -> Clash
The made-up weakness here is Crash Bomber against MetalMan, since there is no QuickMan. But wait, wasn't WoodMan also supposed to be weak against Air Shooter? Hmm...
Magnet -> Hard -> Top -> Needle -> Magnet
Here's the first example of what I mean by two broken rings. SnakeMan doesn't exist, so Top Spin now works well against NeedleMan. SparkMan and ShadowMan don't exist, so now Needle Cannon works well against MagnetMan. All the other damage values are straight out of the NES game, plus a couple of secondary weaknesses to the MM2 weapons thrown in to help you jump into the ring.
World 3Shadow -> Spark -> Snake -> Gemini -> Shadow
Once again, two weakness rings were tied together. As there is no Needle Cannon, SnakeMan is weak to Spark Shock, and as there is no Top Spin, ShadowMan is weak to Gemini Laser. Retaining the secondary weaknesses to Shadow Blade makes it THE weapon to have.
Dust -> Skull -> Dive -> Drill -> Dust
Now we're back to a single break in the ring. There's neither a Ring Boomerang to use against DustMan nor a ToadMan to use Drill Bomb on, so now DustMan is weak to Drill Bomb, though it's still not that effective. Incidentally, I think DiveMan may be equally weak to both Dust Crusher and Skull Barrier now, but I'll have to check for sure sometime.
Now why did this game need four guys whose names start with S and three guys whose names start with D?
World 4Toad -> Bright -> Pharaoh -> Ring -> Toad
This should be getting pretty obvious by now. I mean, the selection screen starts you on ToadMan, and pushing Right takes you through the weakness ring. The ending even shows you what weapons to use. Like DustMan, ToadMan only takes double damage from his made-up weakness rather than the standard triple damage.
Crystal -> Napalm -> Stone -> Charge -> Crystal
Just as obvious as the first set. I think CrystalMan may take the usual triple damage from Charge Kick, though, since it's hard to use a ground move on a guy who jumps and floats all the time. What's really interesting is that all 8 Robot Masters in this game have a secondary weakness to a boss from the opposite set of 4, with the exception of StoneMan, who's weak to Ballade Cracker--because what are ya gonna do, make him HALF-frozen by the Flash Stopper? Taking this into account, you could say that Crystal Eye is PharaohMan's true weakness, since Flash Stopper's actual shots only do 1 point of damage, or that Pharaoh Shot is NapalmMan's (or even ToadMan's) true weakness, since you can charge it up to triple power.
So does this mean that WaveMan should be weak to Gyro Attack? I mean, in the game that would logically follow this one, he would be...
Xtreme 1Storm -> Flame -> Chill -> Spark -> Armor -> Morph -> Magna -> Wheel -> Storm
Flame Stag takes the place of Flame Mammoth, basically. Maybe Spin Wheel was chosen as Storm Eagle's weakness because its charged form resembles Chameleon Sting's uncharged form, but I don't know. What's really interesting is that even though Morph Moth was given a made-up weakness to Rolling Shield in order to create this ring, he's still weaker to his original weakness, Speed Burner. Also, if you follow this order, the only item you'll have to backtrack for is the upgrade capsule in Morph Moth's stage, since I believe you need Spin Wheel to break the floor. (Now how were you supposed to know that floor was breakable without having played the original X2?)
Xtreme 2 is just too mixed up for me to bother with now...