I kind of prefer when a game switches your party up over the "here's everyone, enjoy" route. Largely because it forces me to use characters I probably would never normally use. When I get everyone, and especially if the game uses a customization system that lets everyone be everything, I find I just stick to my faves. I've played FFVII and VIII half a dozen times, but I almost always resort to using my default party option regardless of how hard I try to branch out and "use everyone". The get everyone from the start only works on two occasions: if the the whole cast is equivalent to how many characters you can use, so for example, you can use four characters and there are only four playable characters to use; or if every character is heavily specialized, forcing you to have to use everyone at some point to make things easier.