It's very doable. Fomorian is actually a little more annoying than regular troll though given their very low mental attribute maximums.
Troll deckers can dump attributes because their mental maxes are so low and they already have bonuses to physicals that they don't need further investment in.
So:
A Troll
D Atts
E Mundane
B Skills
C Resources
will get you a low 'ware R2 deck decker that is perfectly functional. A datajack and Narco and some Psyche/Cram goes along way, as does the Perfect Time/Overclocker combo. High edge will help out with decking too. With Skills B, you can but skillgroup points into Electronics, max hacking, decent Ewar, and have points in all around shadowrunning skillsets (a weapon, sneaking, some social, perception, etc.).
An alt model, especially for a Fomarian (which has even lower mental maxes), is to go E Atts and D adept, and shove some of that edge into adept powers and magic qualities. Spider Mentor and some improved ability hacking/computer go a long way when your mental atts are low.
Some folks recommend skills C, but I find that it doesn't really lead to builds that make troll deckers better deckers, and then they miss out on some other necessary running abilities.
Also, best not to compare character generation to D&D. It is pretty different.
UPDATE:
Couldn't help myself, prob too detailed for a new player build, but I did mock up a fomorian adept decker.
All I did was buy ware, a deck, and assigned active skills and qualities.
Karma Remaining = 5 (-12 fomorion, -10 nuyen, - 23 positive qualities, + 25 negative qualities)
Nuyen: 40k remaining for more gear/'ware.
Psyche and Cram (combined with Narco) will give bonuses to Intuition, Logic, Reaction, and physical initiative.
== Personal Data ==
Street Name:
Name: Unnamed Character
Movement:4/8 (1m/hit)
Swim:3.5 (1m/hit)
Karma: 0
Street Cred: 0
Notoriety: 3
Public Awareness: 0
Troll(Fomorian)
Composure: 6
Judge Intentions: 7
Lift/Carry: 9 (75 kg/50 kg)
Memory: 6
Nuyen:40,005¥
== Priorities ==
Metatype: A,4
Attributes: E,0
Special: D,1
Skills: B,3
Resources: C,2
== Attributes ==
Current Form:
BOD: 4
AGI: 2
REA: 3
STR: 5
CHA: 3
INT: 4
LOG: 3
WIL: 3
EDG: 3
MAG: 4
== Derived Attributes ==
Essence: 5.48
Initiative: 7 +1d6
Rigger Initiative: 7 +1d6
Astral Initiative: 8 +3d6
Matrix AR: 7 +1d6
Matrix Cold: 5 +3d6
Matrix Hot: 5 +4d6
Physical Damage Track: 10
Stun Damage Track: 10
== Limits ==
Physical: 6
Mental: 5
Social: 5
Impassive [-1] (Does not include Intimidation.)
Astral: 5
== Active Skills ==
Automatics (Submachine Guns) Base:4 Pool:6(
Computer Base:5 Pool:13
Con (Fast Talk) Base:1 Pool:4(6)
Electronic Warfare Base:6 Pool:9
Etiquette (Corporate) Base:1 Pool:4(6)
Gymnastics (Climbing) Base:1 Pool:3(5)
Hacking (Devices) Base:6 Pool:12(14)
Hardware Base:5 Pool:8
Perception (Visual) Base:4 Pool:8(10)
Sneaking (Urban) Base:6 Pool:8(10)
Software Base:5 Pool:8
== Knowledge Skills ==
== Qualities ==
Addiction (Mild) (Psyche)
Addiction (Mild) (Cram)
Adept
Arcane Arrester
Drug Tolerant
Impassive
Jack of All Trades Master of None
Mentor Spirit (Spider)
Overclocker
Perfect Time
Thermographic Vision
Weak Immune System
== Powers ==
Combat SenseRating: 1
Hang TimeRating: 2
Heightened Concentration
Improved Ability (skill) (Computer)Rating: 3
Improved Ability (skill) (Hacking)Rating: 3
== Cyberware/Bioware ==
Datajack Plus Rating 3 (used)
Narco
Nephritic screen Rating 2 (used)
== Weapons ==
Unarmed Attack
Pool: 1 Accuracy: 6 DV: 5S AP: - RC: 3
== Commlink ==
Little Hornet(ATT: 5,SLZ: 4,DP: 1,FWL: 1)
+ Sim Module, Hot
+ Universal Connector Cord (Meter)
+ Commlink Functionality[Camera, Micro, Chip Player, Credstick Reader, Earbuds 1, GPS Guidance System, Micro Trid-Projector, Music Player, RFID Tag Scanner, Shock- and Water-Resistant Case, Touchscreen Display]