they would be better off trying to sell segura (would be easy) and leake alone rather than taking back a bad contract. trading both of those guys wouldn't be that difficult.
In a vacuum, sure. Don't forget though, their stated goal is to "retool" without tearing everything down to the studs. If they look at Myers offense offsetting the loss of Segura (not likely, but it's a well-established point that Dipoto doesn't put as much weight in the value charts as the newly-minted GMs), and they slide Cano to DH, they'd then have...
CF- Mallex, LF- Myers, RF- Haniger, 1B- Healy, DH- Cano, 3B- Seager, C- ???, SS- ???, 2B- Gordon
If they used the money they saved on Leake to jump in and sign Ramos to hit between Haniger and Cano, slid Healy down to hit between Cano and Seager, and signed Galvis/Iglesias/Hechavarria on the cheap to play SS that wouldn't be such a bad offense - at least when Myers is healthy.
They'd still be light on the pitching side but if the holdup is which prospect they'd be getting back and it was Chris Paddack, Michael Baez, or Cal Quantrill, he would probably slot into their rotation with Gonzales, Sheffield, LeBlanc, King Felix, Swanson, whomever after the break. If they turned around and traded Diaz to the Braves or someone else for a young rotation piece or two (Wright or Touki for example), they probably wouldn't be awful.