It depends on what your using your ships for! Vast majority of Iran's blue water operation are mainly about providing escort, anti piracy & anti terrorist operations and a Helo & UAV carrier/ Replenishment ship is far less of a perceived threat than a cruise equipped +40 land attack cruise missiles + large number of medium ranged SAM's getting within 1000km of U.S. Island bases let alone U.S. or European shores so you have that backwards
Also in term's of cost a Carrier/Replenishment ships would cost far less than a cruiser or destroyer!
And we are talking about Carrier that carrier ~2-4 Helo's(under $20Million worth) + 2 MALE UAV's ($2Million) + $5Million worth of Jet powered UCAV's + $5 Million USD worth of various Quads (At max no more than $40 Million USD worth of various Iranian build Aircrafts, UAV's & Quad's onboard.
For what missions it would be used for would include
1.Replenishment ship for other ships in the fleet
2.Anti piracy and anti terrorist operations
3.Deploying mines and anti mine operations with limited anti sub warfare capability with quads capable of deploying small depth charges....
In terms of getting your money's worth Quads can be far more useful than helo's in various aspects where you don't need to transport troops or deliver heavy payloads.
In terms of speed you would NOT need a ship that's any faster than Iran's 200 meter long Kharg class replenishment ship & in terms of armament aside from the Fajr 27 Cannon you can even fit 2 twice as many weapons you have on the Mowj Class
All Iran would have to do is reverse engineer the Kharg Hull and engine and simply redesign the top deck
So all your really doing is adding an upgraded replenishment ship to the fleet