I understand your reasoning here but I fundamentally disagree and I'm going to use the T-word. Trap Feat. Sorry. That's what it is - "Are you too simple for mathematics? Do you not understand planning a character? Are you terrible at assessing the real game value of stuff? Do you want slightly complicate your character for a gain so small it's hard to even measure? If so here's a Feat for you!"
It's so bad that it's a goddamn Trap Feat.
And it's up against feats like a BETTER version of Magic Initiate, Lucky, Alert, Skilled. Those are also first-level Feats. All but Magic Initiate make sense for the same kinds of PC as Savage Attacker. It's awful. Even Toughness would be a better use of your L1 Feat.
Like, if we score L1 Feats from 1-5 as you suggest, it is absolutely not a 3.5/5 Feat, because that means pretty much every single other L1 Feat has to be a 4, 4.5 or 5 lol.
I believe everyone knows the reasons listed by the person to whom you are replying, but are really missing a big factor here. I know all the maths about it and I understand it is not a powerful feat.
The thing is, this is level-1 cha-gen. So much goes into building a character with a life and personality and feel and vibe that you want. This is being forgotten when comparing SA to these other Level 1 feat options. These feats are clearly, like in other TTRPG games, filling the role of interesting, nuancing tricks and 'thangs' that define a character and impact the RP as well as adding effects.
SA was/is bad mathematically, but for its RP purposes its an okay idea. A character who every turn is so 'savage' that they have the possibility of inflicting more damage than someone else might, or that they flat out are stronger, or however the player wants to frame it, is pretty damn kewl. But, when put alongside other damage feats as mentioned, or an ASI, and given that the sparse opportunities for feats was so precious, it felt PRETTY DAMN BAD. The little RP 'thang' was just an absolute fiasco of a purchase for that value.
Now, every character is getting a level one feat. None of these feats are intended to be super powerful, and they are formulated with the character expression in mind. They aren't meant to be precious purchases, but a natural component of the cha-gen - how your character is and came to be, as well as what their output is.
I agree that the other feats are clearly better, but look: I am making a strongman gladiator with an anger problem who has had some fights in the arena, and has been bought by a nobleman and is now on a quest given to him. I want the brutality of his attacks to shine through, and to be above the other level-1s. What should I take - Healer? Magic Initiate? Hell no. Tough, arguably, but that's defensive, and maybe that's not what I'm going for. You comparing them to SA isn't appropriate here. On the contrary, me coming to the table hearing the 'what do you look like?', and telling my party about my roman gladiator muscles and helmet, all the while knowing I'm gonna be re-rolling an attack every turn forever? For simply selecting an option during part of the innate gen process from some other cool options? I'm PRETTY DAMN HAPPY with that.
It's not right to compare it to the other options given that the context and investment to acquire them has been reframed so much. The only trap I see is thinking the word 'feat' means the same thing as it used to.