Well, you guys have to make the distinction of whether they were great in TM or just great and played for TM. If it's the latter, I honestly can't leave Dejagah out of the list of greatest midfielders. He's right up there with MK with the number of games played for top European leagues, even ahead of Nekou and way ahead of any other Iranian player. And I think Bagheri and Karimi can not be left out of the list
As far as strikers, I think we need to look at the various periods of Iranian football: In the pre-revolution era (78 WC), I would consider Mazloomi the best. In the dark post revolution era, pre 98 WC, that honour should go to Mohammadkhani and Pious. And since then, only Daei deserves to be on the list.
We've never really had AMAZING defenders, but I think Rezaei and Hosseini should be honourable mentions.
And as far as keepers, both Hejazi and Abedzadeh deserve to be on the list IMHO.