VERY excited for these and very grateful for the extended length. Some of the 4DA's have been great as 2-parters, but I feel like they sometimes are just a little too light because they can't do much world building. This changes that. Here's hoping that after this we get another set of stories set during season 17, but this time with 4-parters and get a post E-Space 4th Doctor/Adric set.
Can you credibly get an entire series of stories between Traken and Logopolis?
Sure, why not, as long as they don't go to Earth too many times (IIRC Adric just knows it as "the one with all the oceans" or something along those lines) and it ends with "we should really be getting to Gallifrey." The '82 Annual had stories with Adric, the Doctor and K9; the Wiki assumes it's Sarah Jane's K9 and it could be cool to have that trio on audio. Then, with the Doctor knowing the end is near, he sends the dog off to his new home...
Just as a bit of a side note, Guy Adams has confirmed on his website that this is only the third of six stories he has written that have been announced. The most likely explanation is Series 11/12/13 etc. but it could also mean special releases down the line.
I am really excited for these stories for the following reasons:
1) Back in 1980, I rather resented the character of Adric for - as I saw it - replacing Romana, of whom I was very fond. With that adolescent nonsense behind me, I look forward to the what addition of this deliberately awkward character brings to the Time Lord partnership.
2) David Richardson's words about capturing the high concept tone of the E-Space stories makes me think this collection will be truer to style of Series 18 than the otherwise enjoyable 4DAs series 5.
3) The fact that Jonathan Morris (who wrote The Paradox Planet/Legacy of Death) and Marc Platt (The Skin of the Sleek/The Thief who stole Time) also wrote my favourite four-part 4DAs recently is also a good reason to get excited.
4) Four parters are ideally suited to the 4DA (and more occasional 6 parters would be welcome too), allowing the stories to breathe and giving extra time for some Tom-libs!