Would it be possible in a future update to add a feature for requesting the passenger bus?
It's surely a suggestion that makes sense. We already support this, but only at the airport customization level. At some of our airports, like those in the Hawaii, the terminal is so close to the gate, that it wouldn't make much sense to call the Bus, so those specific parkings "knows" the Bus is not needed.
But we could well add it has an user option.
Oh, and when the baggage is unloaded the handler always leaves some bags behind, is it possible to have him load all the bags?
Well, yes, it's just how we made the animation, not the easiest thing to change it, but it's surely noted.