I generally agree with your assessment.
One build I've been toying with is the skillful mystic adept as investigator shaman mage primary (focus on detection/manip/illusion spells) with adept powers focusing on acting as often as possible (initiative) and/or doing the "always on" important things so he doesn't have to rely on spells for it.
I haven't worked it all out yet, but something like:
This build gives him a very reasonable chance to get 21+ on initiative checks and act 3 times per combat turn (based on an initiative of 10+4d6, plus another +4 using adrenaline boost, which is a free action and fairly easy drain to resist). It also gives him "face" skills/spells and spirits just for fun.
A-Magic R6 (2x R5 skills, +10 spells)
B-Skills (36/5)
C-Attributes (16)
D-Human (3 SAP) = EDG 2 to 5
E-nuyen
BOD 3, AGI 3, REA 3 [6], STR 2*
WIL 4, LOG 2, INT 4, CHA 4
*Raised from 1 to 2 using creation karma (below)
25 starting karma + 25 karma from negative qualities (skip positive qualities) = 50 creation karma
30 spent on 6 PPs
10 spent on STR 1 to 2
10 spent on +2 spells known (now 12, max for MAG rating 6)
Adept Powers (6 PP):
Improved Reflexes 3 [3.5pp] (+3 REA, +3d6 Init Dice)
Improved Sense 2 [0.5pp] (thermo, low-light)
Adrenaline Boost 2 [0.5pp] (+4 Init, only drain 2 with your 7 BOD+WIL dice)
Combat Sense 1 [0.5pp] +1 defense tests and free Perception to avoid surprise (uh, yeah!)
Astral Perception [1.0pp] blast astral beings, assense, analyze magic spell, etc.
Spells (12):
Control Thoughts: very powerful, hard to resist (make foe shoot another foe)
Manabolt: blast astral beings via astral perception (or those on physical plane for that matter)
Fireball: area damage, only 3 hits required to land it
Heal: swap for Trid Phantasm if another PC has it already
Physical Mask: hide in plain sight, sneak into places to investigate
Influence: these are not the droids you are looking for... let me in that door...
Mind Probe: what really happened here... what's that safe code again?...
Clairaudience: what are those guards talking about in the other room?
Clairvoyance: who's behind that door guarding the thing we want?
Analyze Truth: don't B.S. me, man...
Analyze Device: oh, that's what this does...
Analyze Magic: let me tell you what that's for...
Skills:
(two free MAG-related): spellcasting 5, counterspelling 5
(5 in skill groups): influence 5 [etiquette/leadership/negotiation, oh my]
(36 individual): spellcasting 5 to 6 [specialize in manipulation] (2 pts), counterspelling 5 to 6 (1 pt), binding 4, summoning 5, con 5, impersonation 5, perception 6, assensing 4, arcana 4
[EDIT: Skills revised due to comment below]
This makes for a solid face, IMHO. This gives him a decent casting pool of 14 for control thoughts (your go-to) and influence, and 12 for the rest. Resist drain pool of 8 isn't spectacular, but it's workable. During play, grab initiation (centering) and a centering foci to start helping with that. Good news is that most of these spells are already hard to resist, so you can toss off lower force spells to keep the drain lower in early play.
Knowledge Skills (12 pts):
Forensics 6, Psychology 1, Sociology 1, Parazoology 1, Biology 1, Chemistry 1, Ballistics 1
Contacts (12 pts):
Seattle Police Detective (C 3, L 4); owes you his life
Fixer (C 2, L 3)
Future advancement:
Generally aiming for +spells known, +spellcasting skill, +initiation, +MAG, and +foci (centering, power, sustaining)
Initiation: more improved senses via adept points would be fun (select sound filter, etc.), but I'd like use the first 2 grades of initiation for centering (resist drain, stacks with centering foci) and masking (to conceal self/foci).
Spells: Likely grab Mob Mind, Improved Invisibility, Resist Pain, Levitate and Trid Phantasm. They are just too much fun. Barriers possibly. More spells known adds huge flexibility and fun factor.