The whole point is that the beta testing phase is supposed to work any problems out before they go live to the regular players. In beta, my understanding is that things, new mechanics and heroes alike, are being tested to see what any problems are, whether they work as intended, whether there are bugs or unexpected side effects, or whether they are too strong or too weak.
In short, complaining about differences between a leaked testing version and the final product is missing the point of doing any testing in the first place.
Now complaining about whether a given hero, like say Aegir, is weak or not based on their release version is fair and reasonable if it can be backed up logically, but complaining that that hero was unjustly nerfed because he doesn’t match the unfinished testing version, which was released against some form of non-disclosure agreement, is not.
Edit: changes to post-release heroes seem to be earmarked in release notes.But there’s no reason for them to discuss changes made before the hero is even considered ready to release.