You can't.
This is the key idea of PokeBase, which goes contradicts the intentions of threads like those you mentioned:
>PokeBase is not a traditional forum - questions should be answerable, not discussed endlessly. - rules page
Also in the rules page, you can find:
>No polls/opinion questions: Questions such as What is your favourite Pokemon? or Who is the best Water-type Pokemon are too open and vague to be useful. You can discuss things like that in Chat.
Based on this, questions/ posts that encourage open-ended discussion with no final answer are not allowed, because they don't well work with the Q&A platform. Discussing hopes or wishes for future games fits into a similar category: they're opinionated, so there is no right or wrong answer. In your example, I could suggest Light and another person could suggest Sound; both opinions are equally valid, which is the issue here. If there's no correct answer, the "question" can't be solved, and it ends up going on forever.
With that said though, Pokemaster has said that he intends to release a standard forum for the site in the future, which would work perfectly for these posts along with others like trade request threads and such. It's been a very long time since we've been updated on its progress, I couldn't tell you if it will be here any time soon.
For the time being, the best place on this website to discuss these things is the chat room.
