Echoes of Time was the one Crystal Chronicles game I never played, but if it is anything like the other sequels then it is not nearly as good, but that could also be my bias.
I remember when it came out originally, and yes, there was a general frustration that we didn't get a "real" FF, but the consensus wasn't that this game was crap. It was a fun -though tough to assemble- spin-off that was well received as a spin-off.
And everyone knew the team that was assembled for this game was built solely so Nintendo would let Square publish on the GBA, because Nintendo did that to try and get Square to support the Gamecube.