Previously users with less than X amount of reputation were able to provide an answer to their question, but then they were prevented from actually marking it as the answer.
Now, users can't even provide an answer to the question, which means that for detailed solutions, they aren't going to come back and answer it in 8 hours in the same detail they know now.
I'd propose a draft answer system (I'm not sure of the actual reason why it was changed from the previous system, but I'll assume it was for good reason).
In the draft answer system, a user would be able to provide an answer to their question and have it saved, but it would be hidden for 8 hours (and not marked as answered). This way, users can both save draft versions of their answer and the answer is not visible to anyone else during the 8 hour period. An improvement on this would also be sending the user an email when the 8 hour period is up so that they can actually submit the final answer (and mark it as answered if needed).
Unfortunately the current system encourages users to forget about their questions and not provide the final solution that solved it for them.