Everyone is still on a level playing field now just as they were before. While there might be some very minor legitimate concerns with the balance of the brand new weapons, for the most part, people bitching about the new weapons being unbalanced are those who simply don't understand them well enough to counter them.
Every single new weapon comes with a pretty balanced downside, no weapon is inherently better than the weapon it replaces. The only reason why people are using all the new scout weapons now is because they're shiny and new, but just like they did with the other 9 new weapons for the other 3 class upgrades, people will gradually pick and choose between the available weapons to meet their playstyle.