It's been a while since I've posted or played Shadowrun, prettymuch BECAUSE I'm waiting for the technomancer supplement to make my favorite archetype playable beyond "have sprites do everything for you". So I may have trouble remembering every point I've made in the past about them.
But, let's see... At base, TMs are to Deckers what Combat Adepts are to Street Samurai. They are intended to fulfill the same role, but do so in a different way, with their own strengths and weaknesses. TMs and Deckers are the "Matrix Specialist" of the group. This is an important role that fulfills a few key duties. Namely, they have to be able to protect the group from matrix threats, they have to be able to halt security (usually by hacking a host), and they need to be capable of stealing data.
A decker is capable of doing all of those things, because the game system was built -for- the decker archetype. All the rules and mechanics were made with how a decker could do them in mind. The TM, however, was clearly addressed afterwards (as evidenced by it literally coming after in the rulebook and getting a tiny number of pages).
The problems start at creation.
Priority selection. A TM uses the same skills as a decker, but also has their own skills. So they need higher
Skills priority. A TM uses all four Mental Attributes, whereas a decker can get away with just LOG and INT (and at least 3 WIL). The TM is also unable to augment their physicals via cybernetics. So they need higher
Attributes priority. Decker's don't need MAG/RES, and can dump their E into it. You'd think though, that TMs don't need Resources, so it balances out... But a E in Resources is difficult for any character period, and most need D in order to afford a fake SIN, armor, a gun, a commlink, a lifestyle, and other miscellaneous gear. This also means that deckers, since their E is already used, they essentially can be a 5 Edge Human or an Elf with no cost.
Then we get to Qualities. There's a LOT of good qualities for a decker. Many of them don't work for a TM (such as Overclocking), and a TM will likely need at least a couple levels of Focused Concentration if they want to make use of their Complex Forms without hampering their ability to hack even farther.
Then we get to the actual gameplay. Well, a decker is very flexible. Just about every time I play, a decker can enter matrix combat with 8+ Attack rating, Hammer, Mugger, and so on. They can output so much damage that everything gets one-shot, while having an impeccable dice pool due to them having 8+ LOG and 5 Edge. With them easily affording every single program (costing only a couple thousand nuyen) they can be fully prepared for any matrix situation.
Meanwhile, a TM will have usually 5 in every matrix attribute, inflexibly, unless they have specifically an Elf who went out of their way to have 8 Attack. If their LOG is their one-maxed-attribute allowed at creation, then they can have a 12 dice pool. Less than a decker, with less qualities to boost it, less Edge... They might both have a specialization though. They have no access to programs--
Programs are worth 250¥. TMs can get ONE for an initiation. At it's cheapest, it's 13 Karma. Is that a fair trade? FUCK NO. Programs may have been originally just a thing to make deckers special, which would be fine, but they have some VERY key abilities that now, TMs cannot do. Like...
Biofeedback/Blackout: The only way to deal biofeedback damage. TMs now cannot do that at all unless they submerge just for it.
Lockdown: Another staple of matrix combat, link-locking people, is again something TMs are incapable of.
And the biggest one...
Hitchiker: They wrote a whole new way to get the entire group to be able to do matrix stuff! It has its own chapter, it's super cool, and it's a big deal. Deckers can do it for 250¥. TMs? Well, you have to use one of your precious submersions just to be able to access part of the game. Fuck you.
There's a huge number of other programs that offer enormous bonuses, like Fork or Sneak. What do technomancers get? Complex Forms! Which are extremely limited, and liable to knock you out if you even try.
Like, let's look at one of the best, most accessible ones. "Diffusion of [Attribute]".
Diffusion of [Matrix Attribute]
Target: Device • Duration: S • FV: L + 1
This complex form entry is shorthand for four different
complex forms, one for each Matrix attribute. Make
an Opposed Software + Resonance [Level] v. Willpower +
Firewall test. If you win, the target’s attribute is reduced by
your net hits. You can’t reduce an attribute to less than 1.
It doesn't look bad at all. Due to TM's struggling offensive dice (they tend to have 2-5 less than deckers) most people suggest Diffusion of Firewall, which is probably the best choice. So let's look at how it'd play out.
A basic host, such as that of a private business, is about Rating 4. That's kind of low for what a player would be running against, but still. Let's use the book's example of what an R4 Host's attributes would be.
"For example, a Rating 4 host might have Attack 5, Sleaze 4, Data Processing 7, Firewall 6." Firewall is second highest because, while security is important, this private business really just needs to squeeze every ounce of processing power that they can out of the host, hence having the DP rating be 7.
So, you target the host, and roll. You've got 6 Software and 6 Resonance. They have Rating 4 (used in place of Willpower) + 6 Firewall. You go for a L5 threading, and on average get 4 hits while they get 3.
Well... You do reduce their Firewall by 1, but you are taking a -2 Sustaining Penalty. So the overall effect is negative. As Edge is a limited resource, and you certainly cannot afford to begin with much of it, I don't accept arguements of "Well I'll use Edge", as they're always given in a vacuum, assuming you have no other use for Edge and will only use it for this specific thing.
Sprites offer another tool in your matrix arsenal, but they gain OS rapidly and can cause you problems. Not to mention, unless you Compile them at a very high Level, they aren't better than just a decker. They have limited Tasks, which a decker could replicate many of with an Agent (who can do these things indefinitely). Never underestimate the usefulness of having an Agent who's entire job is to continually make Matrix Perception tests on your own deck to check for foreign Marks.
TL;DR: Technomancers should be the Masters of the Matrix, in exchange for suffering in meatspace. Instead, they suck all-around.