I dedomed the SST-12 and measured luminous flux and luminance.
(Yes, my LED boards have a very good life indeed when used in my tests. 
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I pried off the dome in cold condition with a sharp knife. This is possible in principle, but there is a risk of damaging the bonding wires, and residues of the silicone and the white potting compound around the LED chip remain, which also simply doesn’t look as nice as it could be. Slicing seems to be the far better method here.
I don’t know to what extent chemical dedoming makes more sense, since I haven’t tested this for lack of suitable chemicals. It could imagine that this could be somewhat difficult since the white potting resin around the LED chip seems to be made of another material as the clear silicone dome.
Interestingly, the maximum possible operating current has slightly decreased after dedoming. Instead of 3.2 amps, this is now only 2.8 amps max., with 610 lm @ 3.41 V (63.9 lm/W). The Vf has not changed.
Luminance is about 40% higher, despite reduced luminous flux. Nevertheless, the XP-E2 offers a slightly higher luminance, with at the same time usually much more appealing tint. With the XP-E2 Torch with even higher binning which is available at wholesalers, even higher luminance could be possible with the good old XP-E2.
This is because the tint of the dedomed SST-12 is anything but beautiful, which was unfortunately already to be expected after the first color measurement. A pure green awaits the user of the dedomed SST-12, as similar as we already saw with the last tested “Yinding 5050” LED. This is not nice and not even tolerable for use in throwers. Although the color location moves more and more towards BBL with increasing operating current, the color quality is no longer usable at lower operating currents.
I recommend LEDs like the XP-E2 (dedomed), Black Flat HWQP or CSLNM/PM1.TG for throwers in the low/medium power range. Even some special emitters like the Osram SYNIOS DMLN31.SG could be suitable for some special applications and usecases. In addition to the higher luminance, these also offer the advantage of a relatively color cast-free light, albeit at colder CCTs.