agreed on everything about the xt4. not worth the upgrade financially. it's not a cpu/gpu that loses most of its relative power in a gaming rig every single year or so. i was happy with a basic nikon body for more than a decade, the xt2 is here to stay for long. i guess the same goes with your xt20+xh1 combo.
i'd rather add a more compact body like an xe1/xe2 later for convenience though.
About the grip, have you ever tried one of those L plate like grips from amazon for example? I have one on the Xt20 and it makes it WAY better to hold. They only cost you like 25€
thanks for the suggestion! with my small hands, i'm happy with the xt2 grip. there's that aftermarket meike battery grip i was eyeing last summer, but i rather bought a set of spare batteries, so there's no point in upgrading.
btw don't you have anything with a pentax mount? i just did a clearance in my basement, garage and attic (400+ kg's of garbage altogether...), and i found a little 50mm f1.8 manual lens with a pentax mount. i'd be happy to send it to someone who could use it.