Agree with Myhdbender, shaman will have no trouble keeping SK alive in Live end game. I have seen monks do extremely well when played well. But swapping the monk for a bst would probably surprise you in that group.
Agree with above. The SHM has zero issues keeping up post 100 and some AA.
Monk vs BST in the same group and exact same gear (ToL T3 Group full) from my experience - DPS was identical, with maybe Monk slightly ahead due to RNG, or not having to throw an additional heal around every so often on encounters. However, the rest of the group's DPS was so much more with the BST in the group. Wasn't even close.
BST > MNK
I get it. My 2nd ever character was a Monk, 96 hour Raster camp. While that char is long gone, I get the nostalgia and Monk was the first class I made when I came back. 2nd was SHM as I was going to 2box and then I found this site and bought CWTN for both. Someone convinced me to grab a Tank, and 1 day later I had a full 6 LOL. I fought forever on the MNK being my driver, puller, etc and Sic the wise, Sic the all-knowing convinced me to switch my driver to the SHD and I never looked back and eventually replaced the MNK with the BST. I now run a BST in pretty much every group I make. aDPS, 2nd heals, nonstacking buffs at higher levels, additional pet tank in a pinch, the list goes on.
Make the switch, you won't regret it.