It would be a major design change that would affect its sea going capability. The Moudge class is still largely based on the Alvand class. Superstructure changes do not affect sea going characteristics, they only change the arrangement of the weapons, sensors and crew. So by changing the superstructure they are just trying to make the basic Alvand design more powerful.
It seems the propulsion will also be different! Also, Iran needs ships capable of firing Land Attack Cruise Missile, Anti Ship Missiles, torpedo's & SAM! I can only hope that this rearrangement gives the Shiraz Class that capability
Although all your warships should have most of these capabilities but in a good fleet each ship should specialize in one thing one for Air Defense operations, One for Anti Sub warfare, one for land attack missions, replenishments, Sub(s), a Carrier for Helicopters, UAV's & UCAV's,....
Iran is a country rich in Oil & Natural gas but we have far more natural gas than Oil.
Unfortunately we also have too many ships docked that makes them sitting ducks.
Maybe Iran should think about building ships powered by natural gas that utilize gas turbines that we are capable of producing at a faster pace used for both electricity & propulsion. We won't be running out of natural gas anytime soon and you can have a larger fleet out at sea.
Also Bandar Abbas is not a good location for large Iranian warships. One bombing run at Bandar Abbas & at least 80% of Iran's Warships & long range naval vessels are gone. Iran needs 2 new very large Naval Bases one at Jask and one at Chabahar and each ship or sub should have it's own dock with enough space between them so that hitting one doesn't damage the other
Bandar Abbas should only be for FAC, Missile Boats, Midget Subs & at max one frigate or corvette same with Bushehr
Now that Iran can build various types of SAM's, Radars & Early Warning systems there is NO reason to put all your eggs in one basket and you can better see an attack coming.....