Warcaster is really really useful feat for every situation, especially that Sorcerers are con proficient and get free spell oportunity attack. It's not melee focused feat, not even close. Advantage on concentration checks is just, amazing.My point is, the shadow sorcerer combo (Hound and everything else) works well enough without devoting 2 melee focused feats.
IMO the feats provide a benefit that's just too fringe to justify 2 full ASIs and the shadow sorcerer's schtick works just as well without them.
PAM turns the Sorcerer better melee than melee character.
So, yes. It's effectively better caster than casters (free advantage for everything, attack rolls, disadvantage against your spells), metamagic and extra hound damage and prone condition and the hound's oportunity attack.
PAM+Warcaster Shadow Sorcerer just burst a melee enemy easily.
Also, With Darkness you can freely move around the map to better position.
That's why It's insane.