I admittedly prefer TNG era Trek novel series particularly the DS9 relaunch and New Frontier, and era-transcending series like DTI, but I am intrigued by TOS era franchises like the defunct Challenger series & the now ending Vanguard (although I haven't read either). As an aside, I have picked up a few recent TOS era books like Cast No Shadow & Rings of Time (and they're on to-read pile once I get caught up on DS9 & Destiny/DS9-related TP novels). So, I'm not anti-TOS.
I also like books that fill in Trek history like the Lost Era, so I'm not an agist per se in terms of TOS.
I was curious what the strength / appeal of Challenger & Vanguard were? I may pick up a few of the novels.
And, getting macro now, whether its more of a challenge sales-wise to create new series in the TOS era that don't feature the any of the original Enterprise Crew? I believe there have been a few Excelsior books, and a series was teased, but never delivered. Is it more likely a TNG era new series / franchise, e.g. Titan, will be more successful due to TNG era series being more "recently"
on TV than books spinning out of a 1960s sci-fi classic like TOS?

I was curious what the strength / appeal of Challenger & Vanguard were? I may pick up a few of the novels.
And, getting macro now, whether its more of a challenge sales-wise to create new series in the TOS era that don't feature the any of the original Enterprise Crew? I believe there have been a few Excelsior books, and a series was teased, but never delivered. Is it more likely a TNG era new series / franchise, e.g. Titan, will be more successful due to TNG era series being more "recently"
