Minimum 2 bats that are at least 15% above league average.
The way that this was constructed just proved that they were not good enough to win a division, let alone make the playoffs. Teoscar Hernandez was the big addition coming off a 130 wRC+ season, he was pretty average with a 105 wRC+.
They followed that move up with Kolten Wong and AJ Pollock. Good additional pieces, but pretty uninspiring pieces if you ask me.
We are assuming Teoscar Hernandez is going to be gone this offseason, so there is an immediate need for a starting corner outfielder. The Mariners also had a revolving door of DH batters including Tommy La Stella, Cooper Hummel, Mike Ford, and even guys like Sam Haggerty. That just can't happen again this year. You have too much talent and there are too many options to not address this need. You must acquire at a bare minimum 2 regular, everyday bats that are at least 15% above league average. This does not include bench bats that play in 70-100 games. This is everyday players that will have 500+ plate appearances.
There are options to get some big-time free-agent bats like Shohei Ohtani (180 wRC+), Cody Bellinger (134 wRC+), and Mitch Garver (138 wRC+). Or you could look to trade for guys like Spencer Steer (118 wRC+), and Josh Lowe (131 wRC+). There are even more underrated bats like Brandon Belt (138 wRC+). These all fill a serious position of need at a fairly easy position to upgrade, corner outfielder, and a DH. There are numerous other guys that could fit this bill. Regardless, 2+ bats in this range should be the minimum expectation.