I've been a proponent of the "cut & cap" plan for burying I-35, and reconnecting Austin, ever since Sinclair Black began sharing the concept a couple (few?) years back.
To see how well the "cut & cap" design works, we need look no further than Dallas' Klyde Warren Park, which sits atop the Woodall Rodgers Freeway.
Below are six videos produced by TxDOT that shows two variations for the future of I-35:
1) "Modified Existing Concept"
2) "Depressed Concept with Caps"
The "Depressed Concept with Caps" option - the cut & cap option - would bring Austin's urban planning into the 21st century. The "Modified Existing Concept" is what happens when TxDOT engineers and staff have the authority to value-engineer Austin's livability.
Hat tip to @happywaffle for finding these.
Downtown Austin Improvement Concepts-6 "Depressed Concept with Caps" [CUT & CAP]
https://www.youtube.com/watch?v=6PD68vSLEMM&w=550