This is good advice
When I do a Black Talon or Esseles flashpoint and I see everyone in the first major fight picking a different target, I tend to hold the group up and explain the basics of focus firing and co-ordination to them. For the fights against Standard/Weak mobs, it s a bit strange as they tend to die very quickly, but the whole group then sees the benefit when we come up against 2 Strong or Elite mobs.
It also helps when I explain that the Heroic 4 missions on planets will need that kind of group co-ordination discipline, and learning it will make people much more popular in groups :P
I tend to steer clear of the Focus Targetting as I do not want to overload people too much, but within my guilds, I do run coaching groups through flashpoints where I introduce those concepts. It is actually quite depressing sometimes, to hear even 50's saying "holy cr4p, I never knew that"...