Deal With It
There’s nothing complex or confusing about iCal’s event entry UI. And with specific fields for each item of data, it is more obvious than Backpack’s — but only for a first-time user, which is the wrong case to optimize for. But to me iCal’s date entry UI is clearly worse, much worse, and the reason why can be expressed by the fact that it forces you to deal with about 10 user interface elements, versus just 2 for Backpack.