No more free advertising on busses which aren't in service will be the main one, although they do it for the Hurricanes as well so maybe Tranzit will keep the trend.
You'd hope that the GWRC and WCC would have some sort of policy in place to promote public transport to events, + Snapper will still be the ticketing system and they're still an Infratil company.
Actually, the main issue will probably be that H.R.L Morison who make up the bulk of WelNix will have their attention on Go Wellington / NZBus and less on the nix, espeacially if there is industrial action.