I have to disagree with what you're saying; I use a bluetooth headset (Urbanista Boston) almost daily for listening to Cutespot and Nettiradio and I never have any hiccups like you describe. There is a real problem though, but it is not related to switching on/off the BT, but the fact that BT is unusable for call reception. The voicecall quality is so bad you cannot make out anything what is said in the other end. I have no idea if voicecall over BT is better on OPX.
Well, there is a kind-of-workaround to that; if LPM is enabled, the device wakes up when you pull it out from your pocket; after that it does react to double-tapping But I do admit that doubletap is a nice feature.
And that is a real bonus! OLED is so nice... Is the quality good?
One thing which I have learned to love is the wireless charging (Qi-standard). It is so nice just to drop the device on the pillow or charging tabletop and not to fumble for the USB port in the darkness. I think OPX does not have that...?