With an aspheric close to the LED (i. e. not in focus, flood), but at the same distance, the beam profile will not change, but the total output will be less.
Comparing the aspheric touching the dome to touching the dedomed die, the latter will have a wider beam, be less intense and have a bit less total output (unless the aspheric is quite small, say, <20 mm, in that case the total output might increase, since the smaller the aspheric, the more light gets lost when it is at dome distance.)
Does the TIR theory still apply when you slice (most of) the dome off?
With MT-G2’s I don’t think it’s as simply as dipping the LED in gasoline and waiting for the dome to come off. We just slice it off, and I think it significantly improves the throw.
Thank you also, DrJones. This is what I suspected but just wanted to hear it from the experts.
ryansoh3: Yes, it should. The remaining stump should be thin, so that the reflected light (even at shallow angles) hits the die again and doesn't escape through the sides.
This may be nearly exact if we assume the dome is a sphere with the led at its center, but looking through the edge of an aspheric at the led in moonlight mode I it appears to be distorted by the dome so that it is visible farther out than it would be if the dome were spherical.
Dr. Jones: Thanks for writing this up. My understanding had been that the increase in intensity from dedoming was a result of the decreased apparent die area, so this is really making me think. If you could answer a couple questions it would really help my understanding and I would appreciate it.
With a domed emitter, the die looks about 2x the actual area. Doesn’t this necessarily mean that the emitter+dome does not follow the cosine law of a lambertian emitter? So, compared to an emitter with a thick flat silicone layer on top (no image magnification, but no luminance increase), the domed emitter would have twice the luminous intensity directly above the emitter, since I=L*A? And since A*W is conserved, W would have to be smaller with the domed emitter.
If an emitter with a thick flat silicone layer on top (so the TIR does not increase the emitter luminance) is a lambertian surface and follows the typical cosine law, I think I am confused how a dedomed emitter can also follow the same cosine law. The intensity directly above the dedomed emitter would be greater than the flat-domed emitter, so if total flux (lumens) is approximately conserved, the intensities must have different angle dependences.
So if the luminance increase of a dedomed emitter can be compared to using a Wavien collar, would a dedomed emitter emit less at shallow angles (even less than the reduced apparent area would suggest) and recycle this light to steeper angles (more directly above emitter)?
Is my understanding correct?
Edit: just found this test of the luminance of emitters with flat domes vs regular dome vs dedomed, which confirms that a flat dome will not have increased luminance over a regular dome.
I suggest that you look here:
It is not updated with the latest LEDs and doesn’t contain XP-G2 either but it is my favourite efficiency and throw comparison. 
Sadly, since koef3 retired from this forum we don’t have as good source of throw information so it’s hard to update the charts.
I have some relative intensity and lumen outout measurements at different slicing height here for the LH351D : https://budgetlightforum.com/t/-/63712