Remember this fact: no matter which ending you choose, the relays are destroyed. Starbrat says so. After he tells you what each of your choices do, he tells you "Releasing the energy of the crucible will destroy the mass relays." This is on the high EMS ending. Until we see otherwise we have to take Starbrat at its word. You die in two of them -- Control and Synthesis. Destroy kills the geth and supposedly EDI, but EDI says non-functionality is worth it.
In Control you are not a slave. You are the boss. Do you have to continue the cycle? No. Will you? In 50,000 yrs you probably won't be able to because the current civilizations will probably kick your ass. Or they will have written you off as a myth again. The reapers will remain in the history books for maybe two to three thousand years, then will be put into mythology of ancient civilizations. You may have a war with the Geth and have to wipe them out.
If Destroy killed only the Reapers, it would be a very easy choice. No one would pick Control or Synthesis. See by having Control and Synthesis destroy the mass relays they screwed the pooch. They made those choices totally unappetizing. If with Control, the mass relays remained intact and fully functioning, then maybe it might be worth that sacrifice if you were to have full control over the Reapers forever. Same with Synthesis.
The problem is there is no give in any of the endings. Only take. Starbrat (Walters & Hudson) basically says "I win. You lose. Game over. Artistic integrity." That's the bitter part of the ending. The sweet part is when Buzz Aldrin says "my sweet." So now you have a bittersweet ending.
Note to writers: if you are going to tempt players you need to lead them down the primrose path gently. You need to seduce them, and they will fall into your trap willingly. It is not necessary to beat them over the head with a mallet. You don't seduce them by having the arch villains championing the bad choices. If you do that, then you have to resort to the heavy handed tactics used at the ending by putting negative consequences on the one choice the completes the player's mission. However if you have trusted friends championing the causes of alternatives, then you don't have to resort to that. You can branch the plot earlier and leave the player in a real dilemma.
Suppose maybe you had Anderson championing the possibility of control? Or had maybe Garrus championing it? Synthesis would fall easily into Joker's area but that would be too obvious..... hmmm.... maybe.... Dr. Chakwas or Dr. Michel? Maybe Liara also thinking about control, but Javik heavily in favor of Destroy, and Liara is your LI. Now there's a conflict. Tali maybe about synthesis since the Quarians have so many cybernetic implants already. See and if Tali is you LI you have another potential conflict. These people instead of dealing with the evil Illusive Man, and the evil Saren only. You don't know what to think. The player might start thinking, are these alternatives really that bad? I know TIM and Saren are but these other people are good people. Now it's not so black or white.