You would need to send feed back to TA directly for a suggestion like that. They own Cruise Critic specifically for cruise talk:
Many of the regulars on the Cruise Critic Antarctica forum also post here.
I fought hard to have the Antarctica Adventures forum created here for the similar reasons you have mentioned - travellers queries were spread all over the NZ, Sth America and Aus forums. This forum has at least provided a centralised location for people to ask questions about something that is so specialised.
But I think (?) you are asking more about a place for the tour providers themselves to advertise on TA. Thats beyond the scope of the discussion forums and more for the companies to discuss with TA. Traditionally TA has never permitted multi day "tours" by bus or ship to be reviewed as its not part of its product plan (so far. There has been a big call on the HUMTAB forum over the years for multi destination bus tours to have their own discussion forum - without success - and I guess cruises fit that too - hence TA buying Cruise Critic).
The forums themselves are for travellers to help travellers, not for the travel companies to advertise or promote in.
We look forward to your trip report thread and I will ensure I link it to the Top Questions once I am back from my own trip in the March.