As a lefty please don’t put a chest pocket on the left breast as so many companies do for any sort of outdoor shirt. Continually snags on my buttstock in positional shooting. Lately I’ve been pulling them off and adding them to a sleeve if there isn’t one there already.
Not sure if anyone else would like this, but I think something like the hybrid combat shirts that are jersey on the torso and nyco on the sleeves. What I would do different is make the front panel nyco too for prone shooting but keep the back in jersey for ventilation and comfort under a pack. Sleeves that can roll up or tighten with Velcro cuffs. The cycling jersey back pockets are a great idea and won’t be a burden under a pack for reasonable distances. Good ventilation in the armpits too.