What happened was the worst case scenario.
No. Not in the pre-1989 world. Back then any successful overthrow of that outcrop of the abyss would have had to be wildly anti-American. And violent. And an unholy alliance of Leftists and Islamists.
And it's hard to picture the more secular democratic groups keeping power...condidering the - inevitable - international reaction...as well as the fact that their popular support was smaller than the Islamists'...then there was the prompt attack by one of the world's most militantly anti-Islamic governments...
Best I can picture, pre-89, is Khomeini
sans the horrible mass executions. Most Iranian exiles will say the same, incidentally.
Now, after 1989 the West has been much more interested in introducing Democracy in the third world...so a better scenario is possible...but I look at Saudi Arabia and I don't think it would have happened.
And no, I don't think Iran now is worse than Saudi Arabia now...and I don't think many Iranians think that either, actually.
Incidentally, the whole history of Iraq over the last twenty-five years would turn out miraculously different without the Iranian Revolution. The US might never have gone to war there. It's very hard to tell what would have happened exactly, though.