I would only have the back of the waist reduced though, it's the place where the excess fabric sits and the front looks fine.
Other from that what comes to my mind is the following:
Ask for the sleeves to be cut noticeably slimmer, the ones of the Barba shirt look a lot more appealing.
Have the height of the cuffs increased. You seem to be a normal/tall guy with long arms I think the cuffs on the Luxire shirt look too small.
Maybe reduce the shoulder seam to seam measurement to 19.25". The Barba shirt does not look too far off in that regard and on the Luxire one it seems as if the seams don't fall on the tips of your collar bone.