Forgoing XP, yeah, but for loot-gathering purposes you actually wanna kill the leader ASAP. If the leader flees the battle, you don't get any loot for the fight. So if the roulette FINALLY landed on a new skill/item you want, aim directly for the leader.You're foregoing loot and XP by just targeting the leader, if the game systems remained the same from the first one as I recall.
I'm a few generations in now. I wish it was a little harder to balance the various limits on your adventuring. The time limit negates the pressure from other mechanics, unless you fluke into a route that leads you pretty deep into a dungeon. Only one run has actually had me start running low on healing items and Technique points to cast healing spells. I need to start drawing maps (quickly, there's a timer) to keep track of routes, what color/kana keys I have and where the matching doors in each dungeons are, etc. The most danger I've had is trying to get one month too many out of my older adventurers and having their max Stamina plummet to critical levels right before I was were going to enter a Feast. Argh.
(I also need to write down a cheat-sheet for what the various stats do until I can keep it in my head.)