Mattes, um ... Possibly only BE speakers were awake and taking a LEO break at the time you all got into this deadly serious discussion? (-;
But seriously, it may also be true that the figurative sense is actually a good deal more common in BE, though I feel like it's also used in AE to a lesser extent. I wouldn't have gone quite as far as 'chiefly,' but 'especially,' as in Oxford, might be about right. Two of five dictionaries in #23 mention BE. But oddly, none of the AE ones do, including NOAD which makes three of six, so it probably doesn't need a BE marking in LEO. I would guess that, after the AE literal sense had traveled east, the figurative sense started as BE and has now come back across the pond, fairly recently; it's not listed in either of my big AE unabridgeds, which are both older. But that's just a guess.
I agree with everyone who feels that the figurative sense is probably more common and that the literal sense can be deduced more easily from the individual words. I wouldn't call the existing entry wrong, exactly, and I see absolutely no need for a note explaining in all seriousness that Eis means ice cream.
But it would be good to add something else for the non-ice-cream literal sense. It's not really about price but about variety or trying something new; the flavor of the month originally might have been a new flavor, to encourage people to try it out. So I don't really think Angebot is the point as much as Geschmack or Geschmacksrichtung or whatever you all agree on, though Produkt might also work.
And I also agree it's essential to add something else for the figurative sense; I would support both der letzte Schrei [fig.] and derzeit total angesagt [fig.] and anything else along those lines.
And of course flavor[AE], flavour[BE].
On the philosophical question, I've said before that it seems reasonable to use Wrong Entry when the only current entry is for a considerably less common sense, because that overall picture of the word's range of meaning is wrong, misleading. I realize that reasonable people could disagree and that starting a New Entry thread has the advantage of making the more common sense findable with the search function until it can be formally added. However, using Wrong Entry might get it added sooner.
Anyway, in this case, since there's already such a good discussion here, why move now? (-;