I think there's something important to say here

I'm not sure if this means "I have something to say to you, it is the following:" or "I think you said some things that were good to say, (and by implication, you said some things that were not good to say,) and I will now paraphrase the good part of what you said as I would have said it:"

like, if you could think things through from first principles, this wouldn't be how you would approach problems like this

Same issue as above, I can't tell if you are trying to say something to me (and if so, what) or if you are offering an alternative to have said instead of what I did say.