DW's version of the FFG should be able to survive nearly any attack using subsonic SSMs (SM-2 is 75% base effectiveness, adequate time for as many as 3 shots at an incoming missile, CIWS nearly 100% effective), should be about 90% effective in shooting down high altitude supersonic missiles if it has a helo up (75% base, plus you usually get a 2nd shot if the 1st misses), and is generally ineffective at shooting down supersonic missiles when no helo is spotting. It has a chance at stopping the first of a SS-N-27 salvo but the interface is too slow for all but the quickest players to shoot down a second.
If you're getting hit by Harpoon or TASMs in salvoes smaller than 10 missiles, you're doing something wrong... especially if they were fired from 15nm out because you get a free shot at them during the boost phase.... OR, you're playing in MP and the lag is making missile targeting impossible.
Against a unidirectional subsonic missile salvo, the standard drill I'd recommend is turning abeam to the threat to unmask the CIWS and engaging the incoming two at a time with the SM-2. If more than 8 missiles are incoming, throw in some chaff...start popping chaff before the first ESM hit and stop after the last.
If the missiles are coming in separate prongs, then if at all possible direct as much SM-2/chaff toward one prong, engaging the other only when you can do so without sacrificing coverage to the first prong. You can count on the CIWS to smack down one prong on its own, but it will have trouble if it's wasting time rotating to cover missiles from different directions.
DW's FFG is so overpowered it can
take on a Kirov and its Shipwreck missiles and win. It should beat subsonic missiles most of the time.