is there a reason why loads of people are gimping themselves by using focustarget instead of targettarget?

[Simulacra]

So your alts target you main all the time for mob targeting purposes. Right, got that. You're basing all your DPS macros on targettarget instead of focustarget and using more macro commands to make sure your alts target your main all the time - in a similar manner to using focus.

The latecy factor? That is highly subjective to the end user's personal experience - it does not make it superior one way or the other, because results vary.
You mentioned using FOCUS for heals... so now you've got macros setting target (main) and FOCUS? So you're actually doing more work and making things more complex.

If you hit TAB (by accident) - do your DPS macros automatically re-target your current "MAIN"? Or do they blast away at another target - potentially in error? (this can't happen with a FOCUS setup unless your FOCUS changes targets)

Again, I'm failing to see the benefit here. You're using two systems (targettarget and focus) to do two jobs - DPS and HEALS. What's the benefit for the added setup time and extra layer of complexity?yes

1 - yes
2 - since replacing focustarget for targettarget doesn't actually cost anything and since latency itself can change even on good connections why not use it and guard against high latency? As for heals I don't use focus - I use target and don't use focus for anything, so it's not more complex, I was simply pointing out that if you wanted to use focus for something you can.
3 - No, tab is in my do not pass list.
4 - not using focus for anything so there's no double up.

here's my target macro on all my shammies bound to the tilde key - I have 5 keys to switch mains if needed

/target [target=Aztrid]

the follow macro:

/follow

here's a typical cast macro:

/cast [target=targettarget] Lightning Bolt;Lightning Bolt

here's a chain heal macro:

/stopcasting
/use 13
/use 14
/cast blood fury
/cast elemental mastery
/target [target=withthose]
/cast  Chain Heal
/targetlasttarget

here's a tank heal macro:

/stopcasting
/use 13
/use 14
/cast blood fury
/cast elemental mastery
/cast [target=target] Lesser Healing Wave

I could remove the [target=target] as it's already targeted

here's a heal self macro:

/stopcasting
/cast [target=player] Lesser Healing Wave
/targetlasttarget

here's a heal the named macro - this one was for thrall in some quest in CoT I think - not sure

/stopcasting
/target [target=Thrall]
/cast  lesser healing wave
/targetlasttarget

I did at one point use a focus macro for melee, but I switched that to
target - not sure if it works as I really have'nt a need to melee.

but if you do need to then:

/follow target

/assist [target=target, exists]

/startattack