Changing offense/defense is a long term commitment, not something I recommend every year or two. Recruit players for your program, don't change the program for your players. That said, if you want to run a different style, early in your tenure is a good time to switch.
Everyone seems to have a little different take on what attributes are more important for each set. You get a feel for what works for you after a few seasons. Consensus seems to be that flex does emphasize and utilize per scoring a little better than others. So if you stick with flex, you'll want to find some more players with an outside jump shot. Generally speaking, at D3 I leave 3pt settings at -2 unless a player is either above 70 per, or above 50 per with a 170 speed/bh/per combo. I'll make exceptions based on individual matchups on a game-by-game basis.
If you switch to triangle, you'll still want to have some perimeter shooting. But triangle also utilizes LP and pass more, ath/spd/bh a little less than the others. Motion and fast break are, IMO, more about playmaking, so emphasize ath/spd/bh above the LP/per/pass.