Unlike other Arrow-verse heroes like the brooding and regretful Oliver Queen, Sara Lance, and even isn’t just a surprising turn of events; it’s an utterly devastating dramatic shift for him.
And one that Grant Gustin looks like he’ll revel in, performance-wise.
As you can probably glean from Andrew Kreisberg’s recent comments to EW, future Barry Allen isn’t going to be a one-note villain, and his backstory will be proof of that.