Water was strongest on DMM simply because of how Cthulu can provide a stackable 3rd frame DEF debuff (and was pretty much the only Hime for a VERY long time) which allows water teams to hit the max DEF debuff which is 50% and thus deal double damage.
But by the time some of the other elements either start getting their own C frames (Thanatoast for example) or the SSR wind Eido with a DEF down debuff (Frasenberg?? is that how you type it?), everyone can easily start reaching the DEF down cap and Water became less and less special. I know there is already Yamato no orochi for DEF down but her poor stats greatly hinders your party.
Meanwhile fire has Svarog's constant 40% team wide damage buff (double of Arthur's) that is on a completely unique frame and can be stacked with all other team damage buffs.
And wind gets SSR Cybele with alot of damage that gets even higher due to crits if its against Thunder.
Wind won't get any proper SSR healer in a VERY long. The closest one you can get is awakening your Gaia who provides regeneration though.
So using Andromeda might be helpful if you're really struggling to heal your team.