Already lost a few. Frankly they all annoy me with how useless they are. Herbert is the only one I use with any regularity due to his repair boost potential, but he also just gained a 'moody' potential as well....
I only lost two people EVER, and they were both engineers. The most useful class ingame in regards to what they do, but they're always in the line of fire too much. Scouts will carry you!
Played 1-13, and they're all kind of good. I never finished 6, because the concept of doing 3 teams was beyond me. I can probably say the series peaked about 4/6, but that's not to say the rest are bad. They're all terrific in one way or another. The best is obviously FF9, but that's a given if you played them when they came out till FF9 did, but that's a product of age.
I'm not sure if I like where it's gone, but that's indicative of modern gaming progression. A lot of handholding and such these days kind of naturally dictate that things will be easier for a mass audience. That said, I didn't finish FF12 and FF13 because they were too hard, go figure.