Ok I write again XD
Well only a short one…

About your question why they put Skinlink in:
My assumption is not that they only made it to give TMs a way to directly connect with devices like Xenon thinks. In my mind its just to be able to still play the Fluff, since not everyone wants to play the cool Technomancer who then has to fall back an put an odd net of mash on his head or implant an Datajack and lose his Essence, when he actually thought of his character in being able to do this all without a device or wire. That it still cost Min. 13Points of Karma is kind of redicules to me and to many others, but that's another topic.
However the Skinlink still provides a TM with an advantage beyond the Fluff and that's the concealability.
Lets say I want to hack a guys Comlink, but its to good. So I ask him to show me his cool looking glasses which I found out are only rating 1. He gives it to me and I inspect it quite amazed and curious. Well with Trodes or a Datajack it would be almost impossible to now plug my wire into the Dataconnector, but since I do have Skinlink I hack his PAN with ease and the guy even didn't recognize.
I know there are phrases and sentences which are maybe misleading if you look at them to close, but may we fall back once more and ask us what was the overall intention about the book? What I found (and that fits especially for the Matrix in 5tth) is that the Writers planned to make the book simple and easy. It might has not worked out so well, but Im quite sure, that most of the things are meant like that, like you read them the first time. And if it is different intended they did highlight it.
With this assumption I may fall back on the other two topics which got discussed here:
TM and PAN: I was reading it firstly like that, that TM cant slave devices to them self. Devices are should be slaved to devices. So Im quite certain, the writers didn't plan to make the book very difficult and ruin the fun for a TM or make it ridiculously difficult for everyone to protect his stuff. Therefor every character can buy one or more Comlinks and just slave his devices to them. (If you can slave them to your Glasses, I didn't made my Mind up and also don't want to.

)
And once more about TM and the Mind over Mashine echo:
It's a way for TM to become a Rig without losing Essence. They still could implant one and I gues gain the Benefits on their living Persona. What they cant do is getting an RCC and use it with their living Persona.
The Pain editor Echo works the same, you can buy it with Essence or with Karma….
However, I think everyone has now repeated his arguments over and over again and I don't believe anymore one of both “sides” will be convinced by the other. But for people who read this post and are interested in how they should play on their table have now enough facts or arguments to decide which side is more convincing to them and continue with their chosen way.