Rolling your ankle has nothing to do with the highback. Straps at the most but really just the boot. the Deuce is a softer park boot and laces have give. TT30's are great bindings. Just get some stiffer boots if you're that worried, stiffer with BOA. Cables don't give.
Also on a landing that can torque your ankle, your just gonna torque your ankle. That's part of snowboarding, if you land wrong you're gonna hurt yourself.
If you really want new bindings, Look at Ride Alpha's, and the higher end Flow Stuff. NXT. They are stiff and that big strap is really supportive. The day they put cant into their bindings I will convert 100%.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping