Your top three are my recurring party. They deal out consistent and reliable damage that you can get very comfortable with. You can pretty much make use of everything Larian wants you to take advantage of with Lae'zel and Astarion in particular.
Lae'zel can throw any of the standard enemies, carry a shit ton of barrels, reliably shove any enemy into an abyss, and jump from enemy to enemy. Not to mention the abilities she gains as Battle Master. Astarion benefits the most from present game mechanics, which is why I agree with him being at the top of your list. There are some situations where Lae gets a streak of misses (tho sometimes I just need her to soak damage so even that isn't too big a loss if you keep her in the thick of things), but Astarion can be made to attack with advantage reliably. Jumping to reposition, going into sneak, second offhand attack and backstab are insanely powerful when he's fully spec'd out. I've had situations where he was attacking from certain blindspots - popping out of sneak from the previous turn, attacking, and going back into sneak afterward.
Wyll ends up being the squishiest, but oddly enough his straightforward play of just beefing up Eldritch Blast makes him less complex than Shadowheart or Gale. Concentration constantly being broken is less of a problem with him. Patch 4 remedied the constant hateboner enemies had for Gale, but it's hard to want to try him out again when the top 3 work so well.
I do think Shadowheart's trickery domain spells can be pretty powerful and will be trying a playthrough with her, Lae'zel, and Astarion next.
