Cant blame some people for using the rc3 but they cant really blame us either for using old versions.
I blame you for using old versions. What're you gonna do about it?
I'm not sure if you know this already, but the aim speed can be changed and it's not even that difficult. There are guides on this very forum on how to get it like it was in 0.56, which is probably how you would like it. One such guide and some discussion about the aim speed can be found here
If we then think about how the different aim speeds affect the gameplay, i.e. whether it's fair or not that some people can aim faster than others, that is a completely different discussion. I would personally say that it's not such a big deal. I would also like to point out that it shouldn't be too hard to get used to different aiming speeds.