Personally I'd prefer a one week break after two week's worth of events. Best balance of getting events and being able to participate in them IMO.
As I'm relatively new (~ 1 month) I'm hurting for affection items, but I can expect that's going to solve itself in time: one can get up to 4.8 female characters' worth per average break week (or 3.8 female + 1 male) from natural stamina regen alone.
I'm also currently trying hard to get more DC, and event weeks are better than no-event weeks for that: I'm merely skipping out on each event's Thursdays, but I get to farm the events for DC for the whole week... overall the current and previous event are really good for extra DC farming (assuming you're new and hence not trying for the best possible unit) - although I seem to recall Shiho's event really wasn't.
Not sure about unit leveling speed, but one should be able to do that mid-event as well off of the surplus charisma, just less efficiently. In the long term one will max everything anyway. At that point the extra gold is only good for basic rolls, while events give you platinum units, silver unit drops, AND level completion SCs.
Of course with two single week events in a row we'd lose out on the half-day stamina carry-over for the second event, but I'd prefer that to having just half the events the JP version is getting.