The Republic military...

Many people have been upset about the scale of the New Republic in the sequel trilogy, and about how its central military appears to have essentially been wiped out with the destruction of Hosnian Prime.

One thing that I feel is worth pointing out, but isn't talked about often enough, is what the Republic was like during and before TPM.
The Republic didn't use to have a central military! Not during TPM, and not in the centuries before that!

It simply didn't need one, because it's not a police state it's a peaceful democracy where members still maintain much of their autonomy.
People tend to look at what the Republic was like during the Clone Wars, as if that is a representation of what it should've been like in the sequel trilogy.
But that is a VERY big mistake in my opinion, because that was the beginning of the end for the Republic, that was when Palpatine had begun using his manipulations to twist this peaceful democracy into an oppressive police state!

In-universe the people realize this too, how could they not?
The Republic had been peaceful and successful for millennia, but then Palpatine came along, centralized all of its power, suddenly introduced a powerful central military, and it all went to shit from there.

It makes perfect sense for them to revert back to how things were during TPM, how they had always been, it's not perfect but it's better than turning into another Empire.

And it doesn't leave them completely defenseless either, because even with their capital and central military gone, the individual member states still have their own local militias.
They can still fight back, and I'm sure that's what we'll see in episode 9, the Resistance will rally local militias and citizens from around the galaxy, and they will all band together against the First Order.

The Republic is very powerful when it needs to be, when it has a common cause to band them all together.
That's the whole point of being a decentralized and free democracy, it wont simply be defeated by taking out its leaders, because its citizens/local governments still hold most of the power.