Roadhog. Keep heals. Replace hook with Tracer's Blink. Give Genji's double jump wall climb passive. Give Soldier's ult so all his shotgun pellets auto-lock on to enemies with no fall-off damage.
Symmetra .. she has the range of moira , right click does what moira damage orbs do, turrets are still there but has mini shields like old bastion , her E will be changed to zarya barrier , and ult can be a tp and a shield generator at the same time but.. the shields generated also serves as a mini zarya bubble ... ones the teammates pass through the teleport they gain a 5 second damage boost