To the extent that Iran has any real defensive capability, they have “stuff” but not much depth so far as I can tell and it all depends on Russian support to keep running, the public pronouncements have the interesting effect of rattling the Persian’s cage so to speak. If they don’t get jumpy and move a few things around it means they can’t or don’t actually have anything important. They aren’t smart enough to do fake blocking moves so every thing they move is a give-away.
But I’ve always said the easy way to take them out of nuclear production is to destroy their energy grid which, incidentally, would take the whole bunch back to 1920. Nuclear enrichment takes large qtys or both electricity and water-——blasting either one will have them skipping laundry days for a long time. It’s not exactly necessary to try to hit the best protected facility they have, which is also the most likely place they have air defenses.
One reason why they wait until now is because they probably now have very real targets, more advanced weaponry, and all other options are truly exhausted. To the first issue particularly, if they hit facilities that are 3 years from completion then the Iranians would only be 3 years closer to rebuilding them. Destroying them just before they go online sets them back to square one. And like I said, the honorable thing to do is to wait until there are no more options. This attack won’t be pretty, or easy, and will cause Israel a lot of international condemnation and scorn (what else is new, I know) but at least they could honestly say that they tried every other avenue and this was a last resort. Worse, Israel will probably take damage and casualties from an attack by Hezbullah in Lebanon and hamas in Gaza. Fortunately Syria is distracted.