I was looking it over and tsunami isnt as bad as I thought, but I did have bad experience with it recently. but I figured the push does work the way I feel like it should, just not on the initial zone its cast.
if the top left corner of the board is zone 1 and you continue to count each zone across the board until you hit the right top corner which is zone 4. Then return to the left mid section counting it as zone 5 and continue across the board until you reach zone 8. the bottom zones will be 9-12. this is to set up an example for tsunami cast and push effect.
So if the mage is in zone 12, the bottom right corner and cast tsunami in the zone above them, zone 8, and chooses to have the spell move along the middle toward zone 5 then any creature in zone 8 gets pushed into zone 4, following the official push rules. Now once the tsunami moves into zone 7 for the next attack push works in your favor. A creature must be pushed one zone away from the caster unlike the first zone it attacked, where creatures were pushed upward from the mage, the mage has an option to push the creatures upward into zone 3 or better yet push one zone away into zone 6. This is how tsunami can be strong, because creatures are pushed into the next zone will be hit again by the attack.
I think my issue was with the initial cast having the creature not be pushed along with the spell. But unless im wrong u can push the creatures in the subsequent zones into the path of the next tsunami attack. tsunami isnt as bad as I thought if it follows the example I have laid out. it can deal a bunch of damage to several creatures and keep displacing them further away from your location. u can have it hit a battle forge in the enemy's backline, dealing 3d + hydro 3 which could do some serious damage or if you are lucky destroy it. tsunami can be useful, maybe not OP, and strongest when up against a swarm deck for more targets hit.