Fair enough. I felt the only fixing it really needed is to allow it to stack. My argument about changing it so it offers a bump in terms of some die roll or another added to the d20 is it messes with bounded accuracy. If that isn't an issue for the person seeking a "fix", than have at it.
Other mechanics still exist, they just accomplish different things IMO. Spells such as Bless and features such as Bardic Inspiration grant bonuses which are random, others such as the Archery Fighting Style grant a flat +2 bonus. But, your point is taken in the loss of granularity. For example: the difference in a flanking or side attack versus a rear attack where you are unseen by your target. Would attacking from behind offer a great benefit than attacking from the side? IIRC in prior editions it was a +1 bonus (side) and +2 (rear) or maybe +2 and +4, respectively. With advantage they are basically equal. Of course, I think the greater issue is the loss of the Rear AC calculation (no Dex, no Shield) which would make the difference--but that is a different issue.
No not really....
This is absurd & the point is made so I'll end with this before continuing with the many more items that grant advantage
Nothing... and just to be certain no GM takes it upon themselves to introduce badwrongfun magic items with static bonuses to their game they removed bonus types. They topped that by removing the idea that you can't get multiple bonuses to one thing by allowing a +n shield +n armor & even +n bracers/cloak/ring of protection to stack. Just to be safe in case a GM truly wanted to do those kind of things they left out anything about body slots that once were used to help prevent silliness by limiting your ability to wear more than one item boosting something or boosting related things.
So no.... advantage is massively overused and they cleaned out the toolbox of competing mechanics along with the structural stuff that might be needed for them... but good news they wasted a page or so on flanking & facing rules that deliberately miss the mark to such an egregious degree that suggesting it was anything but deliberate is an insult to whomever could miss the need so bad as to do that "accidentally"... oh yea... there are like 4 half baked rules for changing how rests work that don't really do much of anything rather than one that does work & some other variant rules that might support things competing with advantage.