Trailblazer is just more Rails on top of Rails. I wouldn’t pay any attention unless it starts getting more popular than it is.
Rails is a framework. A framework is a set of conventions and opinions about how to organize complex logic. The idea is that you learn how the framework does it, so you don’t have to learn how each individual coder does it.
Rails is already convention-heavy and opinionated. The problem with most Rails projects is that people don’t follow the conventions and don’t believe in the opinions. That’s generally okay because the framework constrains you from making decisions that are too bad. But it’s a mistake to think that more convention and more opinion is what’s needed. But that’s what Trailblazer offers.
Individuals are going to use Trailblazer to make already-opinionated Rails even more opinionated, but that’s not going to make everybody do it.
The next big thing in web development, if you ask me, is React. Back-end organization is pretty-well handled by the conventions that Rails set out, so all new frameworks use those conventions. Front-end logic still needs a proper overhaul. In my opinion React is going to win that battle.