As far as I'm concerned, there's no real way for the game to get better or worse, as long as it is playable. Like the dozens of posts say, if you do not like something added, do not use it, or better yet - do not update.
Minecraft is an amazing game, and always will be as long as there are dedicated players. We have the ability to modify nearly every aspect of the game through Mods & Plugins. The files are at our fingertips, there is no reason anyone should be forced to play with content that they do not like unless they are simple too lazy to do something about it - and lack of knowledge is not an excuse, people are capable of learning to do this stuff.
I think the new update is wonderful. I don't think I need to explain why, but the short version is.. they're giving us new toys. Whether we choose to use them or not is in our hands, and I'm positive the things people use these new "toys" for will be amazing. It's opening up a whole new dimension of creativity for us, things that couldn't be done before have become possible. How can that be a bad thing.
And I wont bother discussing whether or not vanilla Minecraft is getting better or worse, because vanilla is irrelevant in my opinion.