Probably better to let you pick them. Its not like picking character attributes is not part of d&d, no matter how attributes are generated they are distributed by the player in an optimal way. For the example of shadowheart, dex is a secondary stat for a medium armor cleric, on par with constitution. Thus it makes no sense for her to have 9 dex, and no player would pick this on tabletop or otherwise. So even if the devs intention is to simulate rolled stats (which is itself odd given they are all point buy stats just distrubted badly) they fail to do this even then since a player would have put her strenght or cha roll into that dex instead.
Of course it seems all the companions simply have the default suggested stats for their class under their racial modifiers. Shadowhearts wisdom would probably be 15 right now if the default half elf +1s did not include one being into wis by default. This leads me to believe they have simply not set what the companion stats are really meant to be yet, have always intended to let players pick but did not implement it yet, or intend on adding a respec option at some point.
Still important to nag larian about this though since shadowheart is not the only companion that could do with some tweaking.
