I hate that people present Annie as some babbling fool for being in love or the opposite which is downplaying the connection they have to make it seems she is greater if she is alone.

Both Miss the point! Love has been presented as a strength!

+1

It's the example of beauty in a cruel world.

She found a catalyst in her love to actually do something good she chose and grow of her selfishness. It made her stronger!

So what if she blushed. She found meaning in her life thanks to it.

And not only her

+2

What about Armin then? They don't say anything about how he spent 4 years talking to a crystal because she was there and it was his only lifeline to not succumb to the world that was eaten him alive.

It made him stronger! It gave him reason to push.

3+

And this not only applies to them. So it did for Eren and Mikasa, or Niccolo.

Love has been presented in general as something positive and strengthening.

So no Annie didn't regress nor is it bad she is in love. She became who she always wanted in part thanks to it.

4+

Downplaying it also won't change the fact that is has been good for both, not only in development but also in their arcs.

Both became greater characters because of it. And what truly shows it is this panel.

The character growth just here is amazing.

And finally this particular case is so important for the themes of the story.

Because the most nihilistic character found herself in part thanks to that caring boy.

And the one who always fought for peace and understanding found his soul mate in a former enemy.