Blizzard has officially given Overwatchplayers a heads-up warning that when the next big patch rolls out, they'll need to reinstall the game. In the age of bandwidth caps, it's an annoyance, to be sure.
"The next major patch will have some pretty fundamental changes to the game client," a Blizzard rep noted. "The number of back-end changes we're putting in is substantial enough that we can't just patch over the current content efficiently. As a result, when the next patch comes out, the client will fully reinstall itself to handle these changes. We know that this isn't ideal for people on metered connections, so hopefully this announcement helps you prepare for this coming update."
The exact timing on the patch is unknown, but it probably isn't too far off. The latest Overwatch hero, Ashe, just joined the PTR for a round of playtesting at the beginning of the week.
The next major patch will require a full reinstall [Blizzard Forums]