Nah m8. You need a strong healer and a dps healer in zennys case or Lucio for speed boost. Ie (moira ana or mercy) and (Lucio or zen) sym isn't a support lmao
I usually prefer heavy healer + zen or lucio combo.
Like ana+lucio, mercy+zen, moira + zen etc. Regardless the heavy healer, but i prefer zen over lucio, except on control point map Lucio is the man.
Definitely comp and map based. Also skill based lol, Lucio and Zen put out some good healing but don't enable your tanks to be aggressive except on the beat drop. Having two secondary healers does have its perks with two defensive ults but I'd rather have someone who can put out crazy heals.