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.