Ok, time for another mixed bag of bold Proposals

There are two very valid issues about TM playability that need to be adressed:
- The need for high mental Attributes (esp. for certain metatypes like Orks and Trolls) to function at all.
- The need for Submersion/ECchoes to get some basic functionalities (Programms, Skinlink, Control Rig…) for many character concepts.
So I brainstormed a little bit to find ways of getting around these problems without going too deep into „errata territory“.
First of all: Why do TMs need these high stats in every Mental Attribute and why is that a problem? Unlike Deckers, they can not reconfigure their Matrix Attributes and they also can not buff them from start with Cyberprogramms. Because of that, if they have a low Mental Attribute (and by „low“, I mean any value below 5-4!), they have a very low limit for every(!) test using the related Matrix Attribute. This means that they will probably fail most of these tests regardless of their skill as long as they don´t break the limit with Edge. For example, without Intuition 5 or higher, a starting TM can not find any exotic piece of data (Threshold 5) in the Matrix. This is a big problem in general, but especially if you want to play a Troll or Ork.
So first, lets think about ways to go around the limit issue. You could think about Qualities, Echoes or CFs that let TMs buff their matrix limits without buffing Matrix Attributes or the Mental Attributes themselfes. You could also think about using the inherent limit for some tests, the mental limit in particular. Something like this Quality here:
Improvised Hack (5 Karma): This Quality must be taken for a certain Matrix Action (other than Control Device) and allows the Hacker to perform the Action with her mental limit instead of the associated matrix attribute as a limit. (Note: The Test only changes the limit. If you use a Data Spike with an Attack Attribute of 2 (or even without an Attack Attribute at all?), the base damage is still 2 (or Zero, if there is no Attack Attribute in the first place).This is something that would also work nice for Deckers and also some lower-level-Matrix users like Faces or Covert Ops. Mancers would probably use it for Actions like Crack File, allowing them to be decent Data-Stealers without having high Charisma.
But why are we only talking about Mental Attributes here? Does the Resonance only pulse through the TMs brain and nerves and not also through their blood, bones and muscles? Does every Mancer have to „abandon“ his physical body to become a true Master of the Matrix? What about an Echo like this:
Somatic Resonance (Prerequisite: Skinlink): You have learned to use every part of your body as a conductor for your technomantic Powers. As long as you have established a direct link to a device via Skinlink, you can use your Physical Attributes instead of your Mental Attributes to determine your Living Persona (Body=Firewall, Agility=Sleaze, Reaction = Data Processing, Strength=Attack). This works only for Tests interacting with or defending against devices you touch with the Skinlink.This would make for an interesting new way to play a Technomancer: The „Technobrute“. As a Troll with this Echo, you could simply stretch out your long Troll Arms for a surveillance camera, a Drone or an enemies Weapon and fry it with your high Strength-based Attack Attribute, probably with scary pulsing veins and trembling muscles (Yeah, you could probably just physically sqeeze it to death as a Troll, but this is much cooler IMO). One could also imagine a high-Agility Covert Ops TM, using direct connections with high Sleaze to open doors and circumvent security devices.
There is just one huge problem with that: You´d still need to undergo Submersion for that, so this concept would not work from start, just like playing a TM as a Rigger. This brings me to another topic: Streams and Paragons.
In SR4, Streams and Paragons worked just like Magical Traditions and Mentor Spirits: Resonance Streams allowed you to tweak the kind of Sprites you were able to compile (there were more than 5, of course) and the Mental Attribute used to resist Fading. Paragons, at the same cost of a Mentor Spirit, granted bonus dice on certain test (sometimes even outside the Matrix, like Idoru), with an additional psychological tick or whim for balance and flavour.
And this is nice. Really, you could keep it that way and everyone would be happy. But you could also go further and use these mechanics to really tweak the TMs concept. Instead of just swapping sprites and the Fading Attribute, you could also switch the way Mental Attributes are used to determine the Living Persona, or even grant Echoes and bonuses from start, balancing them by denying other features, weaknesses or by additional karma costs.
Some examples for new Streams in this fashion:
Somathematicians: These TMs are all about physical interaction, relying on their whole Body instead of their (sometimes pretty weak) Mind. You start with Skinlink and Somatic Resonance. However, whenever you take more than 1 Point of Matrix damage, the Damage is split between your Stun and and your Physical Monitor.Dronomancers: This is the Stream for the typical Techno-Rigger. You start with the MMRI Echoe. Also, your Machine Sprites gain the Ability to jump into Drones with a Komplex Action (3 Marks needed), supplanting the native Pilot Programm. The Pilot Rating is equal to the Level of the Machine Sprite. However, Dronomancers can only compile Machine Sprites. (They can probably learn to compile additional sprites, but they need to use/waste Echoes for that).Dreamscapers: These often very powerfull TMs perceive the Matrix as a Dreamworld. Dreamscapers are more reliant on their subconsciousness when using their Powers, so they use Intuition+Resonance instead of Willpower+Resonance to Resist Fading. They also start with two Echoes of their choice and a free Hitchhiker Programm to drag allies along in their Dreamworlds, and they get the +2 Bonus from Hot Sim VR on their Resonance Skill Checks as well. When entering a Foundation, there is a much higher chance that the Foundation´s Paradigma is something the Dreamscaper can relate to. When unconscious or in REM-Sleep, Dreamscapers can still wander and hack the VR. (Probably a good candidate for an Echo?) However, when their Stun Monitor is filled, Matrix damage can overflow into physical Damage. But the biggest weakness of the Dreamscapers: They can´t percieve the Matrix in AR (at least not with their living Persona. However, the Matrix looks warped and false to them when percieved through AR Glasses and the like), and if they want to „wake up“ from VR, they need a Komplex Action and a Willpower+Intuition (3) Test, even if they are not link-logged. These are three examples for „exotic“ TM Streams, but you could still add streams with less invasive changes in game mechanics (a.k.a Attribute and Sprite optimisation). The Resonance Stream of a TM should describe how her powers and her own "version" of the matrix feel and look like. There could be a Stream that makes the TM percieve the Matrix more as the endless lines of ones and zeroes below the code, or a Stream where everything is about language and grammar (After all, Informatics are also rooted in linguistics) or even "religious" Streams where the Matrix seems as filled with Omens, Prophecies, Miracles ans Saints (In the german SR lore, there is a group of AI-hunting Christian Techno-Inquisitors in Westphalia Free-State, for example).
Just as with the Streams, Paragons could be used to grant these kind Echoes and bonuses from the start, probably with a smaller scope. And they can also add a lot of Fluff!