There are some thoughts why we do not need to support that in hints:
- Support of regexps in hints was undocumented feature, so it probably had not been used.
- Answers in hints are different from answer in problem. Here, user input is compared to hinted_answer, and proper hint will be displayed. Even if somebody have beed used regexp hints, this will not change users progress over the problem, but only will not display proper hints.