Dickies Arena. What a name.
Once Dickies Arena opens (2020 or 2021 FWSSR), the FWCC Arena will be coming down. New convention space to match what is across from the Omni will replace it. And hopefully they'll straighten Commerce St back out in the process - that is at least being considered.
TCU will not be moving any MBB games from Schollmaier. Anyone who has listened to CDC speak for years about how he'd never move FB to AT&T knows that he wouldn't move MBB.
The $450 M price tag is insane, but Arlington is spending over $1 B on a baseball stadium. The Arena will be used more than you think with FWCC Arena closing. And I'd expect we see a minor league hockey team move over. Maybe the WNBA from Arlington team, too. There will be more than enough events to justify the space. Hopefully it puts FW on the concert map, too. The Arena should see the redevelopment of the 7th street corridor expand even more to Mongomery, too. I'd expect more new restaurants and shops to replace some of the things on that street to compliment Taco Heads and the few things hay have been popping up.
As to capacity for the tournament, I disagree that the capacity is much lower than other venues hosting the first two rounds. At 14k, Dickies will be 3/4 the size of AAC in Dallas. And that capacity number may be higher for basketball if the 14k capacity number is the rodeo configuration. It won't host a Final Four, but it fits right in with the first/second round locations. 2017 first and second round locations were: Amway Center Orlando (20k), Harris Bradley Center Milwaukee (19k), KeyBank Center Buffalo (19k), Vivint Arena Salt Lake (20k), Bankers Life Fieldhouse Indianapolis (18k), BOK Center Tulsa (18k), Bon Secours Arena Greenville (16k), and Golden 1 Center Sacramento (17k). Im assuming Dickies will have a basketball capacity if at least 15k. So it's on the low end but reasonably in range if it's a high-quality venue.