Also, Toady never said anything about 3rd party interfaces directly. He's always focused on the support and source code aspect. Those he won't ever provide, so...
He's said many times that he doesn't enjoy the idea of "essential 3rd party programs" for DF, he will NOT create an official API. He tolerates the current utilities because of deficiencies in the current DF interface, as long as they are not accessing too much of DF's inner workings.
That's not what I am reading from him. To me it seems he doesn't care as long as it doesn't try to steal his stuff, or require his support. Of course that means it cannot be essential, because he doesn't have to think about compatibility for that tool or integrate it. This wouldn't be true if he went the multiplayer support route though.
Peterix was temp-banned but later unbanned by Toady when Toady figured out that Impaler was using Peterix's work to backend DF. Jonask and the Stonesense team are not going to do it because 1. it's tough as hell and a bitch to maintain (Every update to DF breaks Stonesense as it already is) and 2. They respect Toady's wishes.
Look at your statement there. Was he banned for trying to make the program send commands to dwarf fortress? Nope. He was banned because Toady thought he was responsible for an attempted theft of the source code.
Not being a programmer, I don't know of all these issues you guys talk about when it comes to transferring simple keypress information. I do know that I once used a macro program that was able to send complex commands to dwarf fortress. It did it by sending the key commands to the program, and you could watch every step of the program be performed. Whatever was used there would work just fine in a visualizer, if the visualizer was programmed to send the keypress information it received in the same manner. But again, I'm not a programmer so maybe it isn't that simple.
See the work on DFterm, and other utilities
I'm not sure what exactly you are referring to. To my knowledge, Toady has never directly weighed in with an opinion of DFTerm or DFTerm2, although I think he might have once in a talk. I can't remember right now. That program is yet another example of keypress information being sent to the Dwarf Fortress program though, which is what a visualizer needs to become a 3d client for the Dwarf Fortress program. Maybe I am missing something? Like I said above, I am not a programmer. I can point to a bunch of different utilities out there that have some of the features I am talking about, until I can point to a collective sum of the whole.
I don't really care in the end, since seeing the fortress in 3d doesn't really provide anything to me. I'm one of the (currently) 295 people who voted Dwarf Fortress over minecraft or both. I would like to see a multiplayer version though, since it'd help me get more people involved, but that would require it to be low hanging enough that Toady wants to make coding changes to the game to facilitate it. I think it COULD happen, eventually. But I don't see it happening anytime soon, since we are talking about pretty big changes to allow a true multiplayer.