The issue is 7th level is actually pretty high a level, a lot of players won't reach that until later in the campaign. Its hard to look at something as "class defining" if the meat doesn't kick in until 7th.I think people need to start wrapping their heads around features as a package instead of individually.
Yes, Innate Sorcery alone is a power buff but not exciting. But Innate Sorcery is not just a +1 and advantage. At level 7, it becomes +1, Advantage, and two Meta Magics a turn. At 20, it is all that plus a free meta magic every turn.
Its actually one of my beefs with the 5e paladin, that their "class defining" save aura doesn't kick in until 6th, that's very late!
I do agree that there is nothing mechanically "wrong" with Sorc's rage, but its not really exciting either. It has almost no flavor attached. I think the idea is that you "go Super Saiyan", but it doesn't really feel that way.
Hell it doesn't even have to be new mechanics. It could be something as simple as, "you detect as magical to spells like detect magic". I mean that really adds no power to the class, but re-enforces the flavor, "I don't use magic, I AM MAGIC".
This continues to be my flavor struggle with the sorceror. Its supposed to be the "innate magic" class, but the mechanics have never really sold that flavor.