I am fine with the companions the way they are. If the rumours that we will get to at least 12 level are correct, that still gives you significant freedom to respec the said characters. Now if the developers want to make it optional for the player to mix/ma it one way or another... that's fine, too. I am fine both ways, actually
I think Gale, Astarion, Lae'zel and Shadowheart are balanced the way they are. I think the stats of Shadowheart are perfect for a multifunctional cleric. She can tank (which is the role she had in my team), she can use maces and finesse weapons.
I am a bit more confused about Wyll. Statwise is he is fine but his stats do not really reflect his backstory... The "blade of the frontiers" who have negative strength and low Dex? I think that 14 intelligence is misplaced. I would go for something of the sort: Str 10, Dex 16, Const 14, Int 10, Wisdom 10, Ch 16 That or he became really lovesick after Mizora and has not trained for months.
