Games:
Diversify more: genre wise and region wise.
More smaller games: Naughty Dog only released 3 new games on the PS4, compared to 4 on the PS3. Imagine if Lost Legacy didn't happen. They've gone from releasing games every 2 years to more like 3. And it sucks.
I don't mind that Sony is putting games on PC, but it really sucks when it looks like they're supporting PC more than they're supporting their own hardware.
Communication:
One of their big failings this gen I think is their communication. I don't think Sony is doing all that terribly, but they have been awful on communication.
It's absurd to me that it took them ~6 months to confirm that by ray tracing, they really meant hardware accelerated ray tracing. BC wasn't much better. They put out a statement a couple days later, but they didn't respond to it past that.
I feel like their current model is to let the games do the talking, but that doesn't work when we are waiting months for games.
They don't have a lovable public face anymore.
System itself:
I think expanding backwards compatibility would be a great move.
Combine it with PS Now, have it so you could download any of the games to your PS5.