A day one patch for Evolve will contain bug fixes and tweaks, as well as some balancing tweaks - mainly focused around a balance of the Wraith's abilities.
The infographic for the recent Open Beta shows that as far as matches won, the balance is mostly on point with Hunters winning only just over 1% more matches than Monsters did. However they did note that the Wraith, which hadn't been available for play during the Alpha, won matches more than 70% of the time and so most of the balancing will be done to this monster to hopefully bring it into line with Goliath and the Kraken. The changes are mostly nerfs, although there have been some improvements to other lesser-used abilities to encourage their use a little more.
In the nerfing camp we have that Wraith can no longer use its warp ability while cloaked, it will now break the cloak and make the Decoy vanish which stops Wraith escaping as much as they used to. The Decoy ability now takes 30% longer to cool down too, which discourages its over-use in battle. The big attack of Supernova is now also less powerful, its damage having been cut for 10%.
However on the other side of the balance, the Abduction ability now has a slight increase on its radius, having been extended by .5 of a metre for a total attack radius of 3.5 metres. The Warp Blast radius has also gone up by another .5 metres too which gives it a damage radius of 8.5 metres. Nice.
Other than that Turtle Rock reports that the Open Beta shows that all the other characters in game are actually hitting a pretty equal balance, with the changes made to Kraken having given it a 52% win rate during the Beta.