I have both the KD C8 and UF-2100, both 5 mode. The 2100 is great for EDC due to its slim design. It is easy to mount on my bicycle too. However, I prefer the quicker mode memory and the throw on the KD C8. The 2100 needs like 2-3 seconds before memory kicks in
Is there a compact light like the 2100 with better throw (similar or greater output)?
Trouble with the compact torches where the head is the same size as the body is that the reflectors are simply too small to provide decent throw. I don't think you will ever find a light the size of a UF2100 that throws well. Your best bet might be to see what compact XM-L zoomer is considered to be the best compromise between flood and throw.
XM-L zoomers don't throw as well as the XR-E zoomers but they flood much more nicely.
As for reflectors, the XM-L's wide viewing angle needs a wider, shallower reflector to throw well. Deeper narrow reflectors don't work well with the XM-L like they do with the XR-E emitters.
Couple lights for you to consider. Small form like the UF-2100 but with SMO reflector. I have the Yezl Z1, which is similar:
N-Light ST50 - Just a hair bigger than the Z1 but much brighter (+ it has a turbo mode), nice beam, throws pretty well and crisp cool white tint. I use this as a spot on my helmet.
New IOS Mini - I have no experience with this light, but you have choice of modes, tint and reflector (including SMO). About the same size as the SB S-mini.