It is bad, because
- They're not questions about real problems yet
- They interfere with others' ability to later post their real questions about the issue
Making up a question that one thinks will be a valid/useful question, when the game is eventually released, will often result in a question that is not quite useful or accurate in its details.
Further, it hogs the rep for that issue, preventing future people who honestly have that problem right then from earning the rep for bringing it to RPG.se.
As a general principle, only people who actually have a problem now with an existing game should be composing questions looking for solutions to that problem. Writing questions in anticipation of future problems with future games messes with reputation, closures, and warps the utility and function of the site unnaturally in favour of established users who know the site well enough to even conceive of gaming the system in that strange way.
There are enough advantages to being an established user who knows the ins and outs of the site. Stealing valid questions from newer users with honest problems just to farm a bit of rep off an anticipated maybe-problem of an unreleased game is not being a good site citizen.