Yes there are so many changes. if think many of them WILL be nice because i can pack more into a sigle command block. But for me it will also be alot of work. I just started to enjoy the power of command blocks in depth after using minecraft for many years. I slowly stated to use them on my spigot server aswell. and now i need to learn again and fix all my machines xD
I hope there will be nice tutorials and maybe even tools to convert certain commands.
anyway i wish they would keep /testfor as an optional command. because things i buildt this way work with comparators. it will be hard to fix certain machines. :S