Like so many other people in this thread, I think managing the chained party order is a pain in the butt.
When I want to change the party's march order, I spend far more time fighting the interface than such a simple task should take. If I want to move the character in position 3 to position 2 (say), it should be as easy as putting the mouse pointer over the 3rd character tile and rolling the scroll wheel up one click, or pressing "2".
I want a single one-click command to ungroup everyone. Have one button just above the party tiles that toggles between "Group" / "Ungroup". When the party groups, it should be to the location of the currently selected character, making the other 3 walk to him.
If I want to ungroup just one character, I should be able to do so easily. It bewilders me that when I'm processing a character's turn, e.g. having him cast a spell then move away, and when I get to the movement part and I need to ungroup him, when I right-click his tile "ungroup" isn't an option (why the hell not?). I have to select any other character, right click the one whose move I want to finish, ungroup him, reselect him, then move him the way I want. (I know I could also drag his tile to the right to 'break' his chain, but nonetheless, WTF are Larian thinking?)
2) Characters Moving in a Chain
So many annoying effects...
I click a location for the party to walk to, on the way the lead character walks into a trap, he keeps walking and the other three members of the party keep walking into the same trap. Even if I'd rolled "3" for all their Intelligence stats, they should've been smarter than this!
If one character enters "sneak" mode, and he sets off to do rogue things, and something happens that takes him out of sneak mode (e.g. he sets off a trap), the other three characters immediately start walking to his location (sometimes walking into the same trap too), usually kicking off a combat when I was absolutely not prepared for it.
At the end of a battle, the ground can have some dangerous patches (e.g. pools of acid, burning oil, etc.). When a character kills the final enemy, the 3 non-selected characters immediately walk to the selected character's location, often taking damage and even being killed by it. This is particularly stupid because they could have easily walked around the dangerous patches, but the path-choosing code had them take the shortest route regardless of how damaging it'd be. At the least, when combat ends have the characters stand still where they are, leaving it to the player to tell them where to move. (Characters choosing damage-dealing routes when safe routes are available is a frequent event, e.g. if I want to jump Asterion over running water, and ask him to jump to the far side of the stream, instead of walking to a dry place that's in range for him to jump from, he'll walk straight toward the destination -- often into the water -- and then jump as soon as he gets within jump range).
The annoyance of unintelligent chained movement is made even worse by Larian's determination to make 'clever' terrains, so we get things like the utterly stupid, poison-gas traps on the way to the Hag's room. I like my D&D games to have at least some degree of reasonableness ("Could the hag and her servants, visitors, suppliers, etc. operate out of a lair that had those traps?"), but in DOS and BG3 Larian often design 'interesting' environments that are unbelievable even in a magical milieu. Having a chain of characters walk unintelligently through areas of terrain that are rigged with incredibly inconvenient traps is a combination that makes for very annoying game play.
I greatly dislike save-scumming in any game, and am very reluctant to load a previous save just because something went poorly. Unfortunately I'm now a constant save-scummer in BG3 because my party members keep doing utterly stupid things just because they are 'chained' together (or because Larian built utterly ridiculous terrain). My enjoyment of the game takes a significant hit every time I reload. I go so tired of this in DOSII that I gave up on that game not even a third of the way through. I suspect BG3 will end up annoying me so much I never play it all the way through either. At the end of a hard day's work, I just want some fun entertainment; I don't want to fight the UI to stop it killing my characters in terrain riddled with ridiculous traps.