(cont...)Lucio can bring his allies to the frontlines faster with speed boost and push opponents around(very useful in KOTH maps because they often have pits) and Zen can actually attack especially someone he sticks a discord orb on. Their other utilities are why they don't heal as well as Mercy.
Ana doesn't benefit from headshots, so you can actually aim at the center of mass unlike Widow and Hanzo for easier shots. Mercy is always going to be the best at healing since that's all she can really do.
@Just Jacque: Mercy is not mandatory. There are maps and situations and enemy comps where other healers excel far better and mercy is a poor poor choice.
Theres no need to treat her as a sniper all the time. on the PTR she proved to be more than capable of mid range combat and healing. You can play her like a McCree and when its strategically more viable, you can pull back to sniping positions.
Mercy is why direct healers are a shit idea in FPS. Soon as you add one they become mandatory. Thought Blizzard would've been smart enough to avoid that trap.
You're probably just feeling angsty about something that has in the past been difficult.
Just like everything else in Overwatch, sniping has been made very easy so that everyone can do it. I don't think she'll come close to ressurect either though, and zenyatta already has the long range heals.