Targeting is not too hard with a little practice. The package will land at the spot right at the bottom center of the screen (in default trailing camera view), just as the spot passes from view. This seems to work regardless of speed and altitude (although I have not tried to make a drop while boosting, so I make no promises there). You can also switch to overhead view to make the drop, but I find switching views tends to disorient me, so I pretty much always stay with the default view.
I kind of like the level of challenge that the game has now and am not keen to see it watered down too much. Specifically, I'm not eager to have delivery target markers on the ground, except perhaps for a tutorial mode, since the whole point of the game is to force you to memorize country and city locations if you want a high score. If the game told you exactly where to go next, you lose that challenging memorization aspect, and it just becomes a matter of following waypoints and hitting space when you fly over the marker, which is not really a challenging enough gameplay loop to hold most people's interest for more than a few minutes.
(That said, night deliveries already have markers of sorts for most cities, assuming you know the city's general location. Your target city, at least for smaller countries, will tend to be the brightest lights in that country. And when it isn't, you just make a mental note that that city was not this blob of lights but that other one over there.)
I think a better "easy mode" for the game would be to have a mode with pickups only (no deliveries), that just counts how many balloons you manage to pick up in ten minutes (or whatever). That might be a little more accessible for people who aren't already big geography buffs to get into the game and start gradually learning the countries, since you can see the balloons from so far away.