While a modern rim may weigh a bit more than that Araya rim, it will be wider for a better tire profile and it will be stiffer, which I like.
A modern double walled rim with a 23mm outer width and 28mm depth is not heavy and I think builds up easier(since it is inherently stiffer). I haven't built many wheels, but even my limited experience was able to tell the difference.
Also, modern wheels neednt be low spoke count. A 28h wheelset with butted spokes and modern rims can be very reasonably light while still being quite strong.
...but the 126mm issue means not using modern hubs.