Finishing move is very situational in its usefulness. But that is a common theme in Shadowrun. Often, being adaptable is far better than being focused and good.
To illustrate the usefulness of Finishing Move, lets look at an actual situation.
Hotfoot, the elven adept, is a brilliantly skilled and deadly martial artist and a first grade initiate.
Muggins the part time bouncer, sometime Syndicate debt collector is nothing particularly special but is a troll. I, as a player or GM in the game, would like to see the brilliant elf fighter be able to beat up a troll bouncer. But what actually happens?
Hotfoot, Adept
Elf, Initiate Grade 1
CODE
B A R S C I L W M E Ess Init IP CM
4 7 6(8) 4 4 6 2 3 6 3 6 14 3 10
Skills: Running 3, Gymnastics (Tumbling) 5, Unarmed Combat (Carromeleg) 6, Dodge (Melee) 5,
Etiquette 3, Leadership 2 (Entertainment). Shadowing 1.
Qualities: Adept
Powers: Critical Strike (6), Killing Hands, Elemental Strike (Fire)*, Improved Unarmed Combat (1),
Improved Reflexes (2),
Gear: Leather Jacket (2/2)
Muggins, Bouncer
Troll
CODE
B A R S C I L W M E Ess Init IP CM
8 2(3) 3 7(8) 1 2 1 4 - 1 6 4 1 12
Skills: Unarmed Combat 3, Dodge 2, Intimidation 2
Implants: Dermal Plating II, Muscle Replacement 1
Gear: Armour Jacket (8/6)
Total Armour: 11/9
I don't think we need to bother checking who wins initiative. Hotfoot goes all in with an unarmed strike.
Combat Turn 1:
Hotfoot rolls 13 dice (-1 due to reach penalty), and gets 4 hits. Muggins gets 2 hits to block. Hotfoot deals (with Critical Strike), a deadly 8P damage. Wow! But now Muggins gets to soak and rolls his 19 dice to soak. Additionally, the damage is converted to Stun due to his armour exceeding the DV. So Muggins scores 6 hits on soak and takes only 2S damage.
Now Muggins gets to take a swing at Hotfoot. Scoring 2 hits, Hotfoot takes a chance and doesn't go full dodge. Hotfoot rolls 4 hits (even counting Reach penalty) and easily sidesteps.
The remaining passes all belong to Hotfoot so we'll just assume similar actions and behaviour as the first one. At the end of the Combat Turn, Hotfoot has got the troll down by 6S. Maybe 7S if the wound penalty has become a factor.
Now lets see that combat turn again with Set Up.
Combat Turn 1:
Hotfoot, knowing its another generic wall of damage soaking that he faces, uses Set Up. Again, Hotfoot scores 2 net hits.
Again, the troll swings uselessly at Hotfoot on his action.
In the second pass, Hotfoot has 15 dice (+2 from last time). That's still not enough he thinks so he uses Set Up for a second time, getting a nice 5 hits. The troll has already defended against a melee attack this phase so is down to rolling 5 dice. We'll still call it 2 hit success for now though. So three net hits to Hotfoot.
In the third pass, Hotfoot is ready to do some damage. Muggins is down to 4 dice to defend. As we were generous with rounding up last time, we'll be fair and round down this time, giving him 1 hit on his defensce. Hotfoot is now rolling 16 dice and scores 5 hits, so 4 net hits in total doing 12P. Hooray! Hotfoot is now
actually inflicting injuries on the troll instead of just dazing him. Assuming that Muggins gets the same 6 hits on soak, then he's just taken 6P of damage.
Can that really be right? Yep - looks it. By chaining some Set Up maneuvers, Hotfoot has swapped doing 6S to the troll over 3 attacks, to doing 6P in one final devastating strike!
Now this is a slightly arbitrary example. It shows how Set Up can allow a highly skilled but slighter of build character to actually damage a fairly standard brute. Facing off against a moderately better armoured opponent it still wouldn't be enough, but then in such situations, the martial artist would probably be using a weapon which would even it out. If the martial artist isn't an adept with a high-level of Critical Strike, then they still probably wouldn't be doing Physical damage against the troll, but then they might find Set Up useful just to score any damage on their opponent at all! Also, you can use the effects of maneuvers with other powers. For example, the Elemental Strike wasn't used but could have been on the final attack, and it would have made the power more effective.
Set Up isn't brilliant, but it is situationally useful and worth having, particularly if you are more the Bruce Lee type than the Bruce Willis type.
Regarding your other question about Stacked Foci - yes, they're very useful (again in the right circumstances). Firstly, they are a way around the maximum number of foci you can bond (you are likely to hit this limit before you hit the limit on total force unless you are exceptionally wealthy). Secondly, it lets you mask "more" foci with Extended Masking than you would otherwise. As you can only mask an additional 1 aura (e.g. a foci) per Initiate Grade, Stacked Foci can be very useful!
Khadim.