Your wording would combo with things like Mana Short, which I don't think he wants. That said, I still don't think that the posted wording is exactly how Wizards would do it.
The main problem I see with the card, though, is the fact that nobody would play it unless it was in a set with tons of awkward mana producers, in which case it might occasionally get boarded in for a Limited g2. In practice, how often did you see mana burn over the course of its run? I don't think I saw someone take mana burn as often as once per tournament. This effect would probably be fine on a 0-cost artifact with flash, which would still see no play, let alone a

enchantment. Maybe do it as a

Instant cantrip with "For the rest of the game, [opponents take mana burn]." Compare to Crimson Wisps, which does
something every time you play it. This would not.