The technomancer in the core book is badly built, and really shouldn't be used as a model. The question you should be asking yourself is:
1) Do I care about being able to do this really, really well? Or just passably? If the latter, don't buy it - thread it up a little when you need it. If the former, buy it at 6.
2) Do I care about being able to do this very fast? Or can I afford to wait a combat turn or so? Do any of the sprites I can summon have this? You should only have CFs if either none of your sprites do, or you expect to need it on a NOW NOW NOW basis. Browse is a good example of a trap - you can just ask a sprite to browse for you.
You should absolutely have the following CFs:
Stealth, Exploit, and Spoof are needed for hacking, and you care about being really good, not just OK.
Analyze is needed for Matrix Perception Tests. No analyze = can't see what's going on, and no defense against being hacked. You can't thread it because you need to make these checks reactively sometimes.
If you care, at all, about rigging - in even a "might want to sometimes" way - you should have Command.
Other CFs you might want to consider:
Disarm: useful for hacking (disarm someone's Analyze once you sneak in so you can't be found)
Shield: Matrix defense - but note sprites can matrix fight much better than you, and you generally want to hide behind a paladin sprite, not fight yourself.
In my opinion, there are no other complex forms worth learning. Everything else either has a maximum threshold of usefulness that you can hit just by threading, can be covered by sprites, or is overly narrow in application.
You might want to check my sig for a few example technomancers (Technoshaman and Info Savant)