While early purchasers of KOFXIV are already reporting that the game has good netcode, there's going to be additional improvements.
According to tweets by KOFXIV's lead game designer Neo-G, the game's day-one patch will not only feature legacy support, but it'll also include additional tweaks to the online. Whether this means there'll be tweaks to the netcode itself or simply that there'd be adjustments to the various modes for online play isn't clear.
The Day-one patch will also include game balance updates; players attending the Premiere events this weekend in Osaka and Tokyo will get to check it out before the official release.
In addition, KOFXIV game designer Hayato Watanabe announced today during the KOFXIV Dream Match Exhibition Tournament that Fuzzy Guard/F-Shiki wasn't intended to be in the game and the developers are currently trying to take it out. There will be a patch when the team figures out how to get rid of it.