Baron should be balanced with the same mindset as everything else.

Much to the chagrin of the majority of players, the game is balanced mainly around Diamond 1 and above. The explanation for this is that they generally play each champion as best as they can be played.

One major downside to this mindset is that particular champs get nerfed into the dirt.

Champions who require team coordination to play (and as such should be encouraged) such as Ryze get completely dumpstered for the majority, with a 40-45% winrate bronze-plat just so they can have a 50% winrate in Master-Challenger.

But if this is gonna be the mindset, it needs to be consistent. Specifically, Baron is too weak to account for the fact high level players know how to press a small advantage into a nearly unbeatable snowball. So it's not uncommon for at least one fed player to have full build at 27 minutes, and make it quite easy to take Baron in under 10 seconds.

My suggestion is that Baron's damage and resistances scale up with the damage he's taking, to force it to be the long Boss fight it's intended as.