I wonder if there is a correlation between religious beliefs and ending choice.
I've seen a couple polls.
The non-religious outnumbered the religious (well whatever, that happens in the nerd demographics).
The non-religious more clearly picked Destroy, but still had some in Control, and almost none in Synthesis.
The religious less clearly picked Destroy, but it was still a very high number (Destroy in itself had a high majority). They had more in Control and Synth than the non-religious, but for Control it was still closer to even, while for Synthesis it was an actually noticeable number compared to the non-religious.
Basically, they were more spread out than the non-religious, even though they still had a distinct majority for Destroy.
Almost no one picked Refuse. (To me it appears that Refuse exists just as a protest choice and not one that most people ultimately went with, even if many were petitioning for the chance to defy the Catalyst and even shot it)
Obviously this is a super broad summary and not to be used as evidence in anything.
For the record, I am an agnostic atheist with acceptance for spirituality.
It's OK to say that the Sheplyst is something of a crapshoot, though, since in advance we don't know the accuracy of the process. But Destroy is also a crapshoot, since for all we know the Catalyst could have been completely right about everything. I suppose someone can come up with a bad hypothetical for Synthesis too.
Citadel DLC covers this.
Destroy, Silver Coast Casino - Gamble, all or nothing but may get highest actual payout
Control, Castle Arcade - Gaming for high score but get a prize of some sort either way, either of physical or virtual nature
Synthesis, Tiberius Apartments - Always a star in your ecosystem and existing with your loved ones, but little actual prize except the feels
(Armax Arena is Yellow, the color of the overall struggle and conflict that all the characters, Red/Blue/Green/etc are going through anyway)
Anyway, what I'm saying is that all the ending choices are a crapshoot/gamble in their own ways. It's just that while Destroy is one of the more definite nature (a literal gamble for the player who doesn't account for EMS and just stays immersed into the story), Control is of the more ambiguous nature (a virtual gamble for the player that will just have to hope everything will turn out alright for this cycle). Synthesis is more of an outright leap of faith that the decision made will work out well for the whole galaxy - let alone the factions/persons close to Shepard or Shepard himself.