I've encountered a few of the items you mention too Red. Though I deal with them via hotkeys mostly. I guess there are certain annoyances/inconveniences that I find work-arounds for vs fixing. Compared to a piece of broken code that ceases operation.
I too have noticed them not always sitting to med, but I started tweaking back in 10 for this issue, and added some additional med checks to my own edition of KA, because I ALWAYS felt they didn't med when they should.
I haven't felt that the bard twist continuing issue posted above yours was quite a bug, but it has been frustrating at times, and I've not addressed it yet, though it does interrupt /camp commands at times.
Have not noticed the casters refusing to fight unless full mana/hp, but that could be an oversight with 12 toons. they might be casting instead of swinging, but the mobs still die, so haven't dug into that.
I've noticed some laggardly rebuffing, and will call the /groupbuff command to get folks freshened up, and it may be related to that point you raised. I saw that in ka11 as well though.
the only buffbeg option I'm using right now is for modrods, here's an example, first from the shammy's ini:
INI:
Buffs16=Summoned: Modulating Rod|begfor|1|alias|modrod
and secondly from the mage's ini:
INI:
Buffs9=Modulating Rod|summon|Summoned: Modulating Rod|1|alias|modrod
and I know it's working because the MQ spam for modrods for a group of 6 casters is voluminous. There is no "command" to beg for a specific buff like you're asking similiar to spellandtell macros, because that's going to have to trigger off events, I don't see additional ones for that in the code offhand.