nope Talent trees will likely be refunded as they shift from 71-point system to a 41-point system. The game will now only allow progress down a single tree until the 31st point is placed in a single tree and the number of talents has been drastically reduced. The Glyphs system will also get an overhaul.
Additionally, many class mechanics are completely changing. For example, Hunters will no longer need to use ammo to fire ranged weapons. Simiarly, soul shards are going away for Warlocks. A list of changes can be found here.
Game servers should be down for around 12 hours beginning at 12:01 PST tonight and should come back online with the patch around noon PST on Tuesday.