Even if Iranians convert to Zoroastrianism (which would break the ranks of world islam and is, therefore, a good thing), we should never forget that Persians have always been the historical enemies of the Western Civilization. Even before they became Muslim, they were Asiatic - barbarous, treacherous, crude. Although their civilization had some great achievements, and they are a lot smarter and more sophisticated than Arabs, they are not compatible with the West. They have historically disliked Western people, and we should keep them at arm's length, even though we should welcome their conversion away from islam.