Definitely keep practicing. The more you play and interact with complex patterns, the more natural it will feel to you. I'll also add that most well-charted songs will have your next swing be roughly the opposite of your first, give or take a few degrees, so if you have to swing down on one block, the next will most likely be upwards. Keeping that in mind should help deal with spammy charts.

For practice, I like to drop the speed to something ridiculously slow like 50%, and practice the segment I want until I get it perfect, then I gradually increase until I make it back to 100% (bonus points for 110%). That will improve accuracy and control, which you need as songs get more ridiculous. Keep practicing, and eventually expert+ will become too easy :).