Considering the amount of time I've invested in the original, there's still so much I don't understand about the inner workings of the characters' abilities. For example, I get that Reyn is a tank and Dunban is an agility tank, basically the same though with a different purpose, but I'm not good at identifying those "roles" right off the bat. Perhaps it's due to inexperience dealing with RPGs overall, I just tend to go with the battle system's color scheme and the attack descriptions to trigger the decisive blow. It feels more intuitive that way.
Early on I'd use Shulk as often as I could, and never really got around to trying Reyn out until my third playthrough (as well as the others). Once I hit Makna Forest, I started maining Riki for draining damage (I love that he's a jack-of-all-trades), Shulk for power attacks, and Sharla for healing/support. Later on when, um, another character came back she turned out to be my favorite, and I traded her with Riki and kept Shulk and Sharla. So, as the more adept players can probably tell, I didn't get the privilege of fleshing everyone out until now. These days I can appreciate Dunban and Melia's assistance a bit more, because a Shulk and Sharla duo can be seen as gamebreaking.
On to the new game, the class system is a major draw-in for me. I'm definitely going to experiment with each class, but will probably stick with a gunslinger/swordwielder combination.
