The Counter-Strike: Global Offensive blog has release notes for a new version of Counter-Strike: Global Offensive that's now available. These mention that some weapon gameplay changes have been reverted, and this blog post has further details on what happened and explains the plan going forward:

It’s difficult to measure the impact on gameplay when too much changes at once. The Winter Update came with some really huge changes to gameplay, including a new weapon, an adjustment to pistols, and the rifle change. Since we likely changed too much too quickly, in today’s update we’re rolling back both the rifle and pistol adjustments to their pre-Winter Update state.

We failed to anticipate the reaction of the community to changes in such heavy-use weapons, and we clearly need to re-evaluate our process for making and communicating about changes in that space. We still think there’s value in trying to find a better balance for pistols and more skillful ways to use rifles, so we hope to tackle rifles and pistols again in the future.

We’re constantly reading community feedback and while we don’t often respond directly, understanding the community is one of the most important parts of working on CS:GO. Mistakes happen, but when they do, we’re committed to making sure they get fixed.