Brier had already run the Commonwealth B standard of 23.07 before the deadline but Team Wales policy is that athletes beat – not just match – that mark for selection.
The Swansea Harrier, who also holds the Welsh 100m record, then underlined her status as the fastest Welsh woman of all time by breaking the national 200m record held set by Michelle Scutt in 1982.
“It’s very difficult for us Welsh athletes because we almost have to come out with our absolute A-game in April or May which is crazy when the championships are in August,” she told BBC Sport Wales.
“The standards are tough but relatively fair, but how early the deadlines are set needs to be looked at.
“It makes me think if I’m running these times now in May, what on earth am I going to be running in August because it’s only up from here.”
Brier was just 16 years old when she competed at her first Commonwealth Games in Glasgow and was desperate to enjoy her last in the same city.
“To be the shape that I’m in now, knowing that I [could] go there gunning for a medal, in my last Commonwealth Games, is really gutting,” she said.
“I said four years ago [in Birmingham] that was going to be my last time and here I am running Welsh records and European standards.
“[But] the way the sport is moving, it’s going to be really tough for me to keep running the standards I’m running in four years time.”