so, to summarize all this verbiage, it's your opinion that a touring tire should be wider than 37. is that fair? i don't disagree.
my point was that there are numerous high quality tires for the 451 size. everything from knobbies to slicks. 451 rims are designed for road and/or bmx racing. the criticism that 451s don't accommodate wider tires is like complaining that a nespresso™ machine doesn't make a 10 cup pot of coffee. it's not designed for that purpose.
maybe a more cogent criticism could be made of the manufacturer itself - the idea that they can simply pop some knobby tires and rack braze-ons on the reach and call it a "trail" bike could probably be questioned. personally, i think a double-walled 406 wheelset with an appropriate fat tire would be better for a bike designated "trail" and definitely better for loaded touring.