If you look inside the Wiggler, the guts are already crammed in there without any room to spare. I can’t imagine how they would fit all of it into a smaller enclosure. IMO, it wouldn’t be a Wiggler any more if you removed the tubes. And if you keep the tubes, you gotta keep the toroidal transformer and the wall wart.

The only design difference I would make is to mount the power jack somewhere other than the side. I might have placed it on the top-side by the jacks, or even the top/corner-face of the pedal just above the knobs.

Both are excellent! And each one has its own strengths.

XO Pulsar:
stereo panning
continuous adjustment of the ramping of the wave form
a switch to change between two waveforms – sawtooth and square
glassy smooth tone

Wiggler:
tubes that aren’t just a gimmick, it really has a grainy warm tone
LOOZ setting, which is a very phasey setting reminiscent of a Univibe
WURL and HAMM settings, which have a very subtle hint of pitch shifted vibrato
ACEY setting for a very choppy sounding trem
A level knob!