Hi, DD. You can certainly place the subject where you did in that sentence. Doing this gives special emphasis to "more important" (it should not be "more importantly"): More important were the people who came here.
Firstly, there is the general strategy of fronting. You move an element to the front of the sentence to give it emphasis.
(1) I saw John at the back of the room. --> At the back of the room, I saw John. OR John I saw at the back of the room.
(2) The rabbit hopped down the road happily. --> Happily hopped the rabbit down the road. OR Happily, the rabbit hopped down the road. OR Down the road, the rabbit hopped happily OR Down the road hopped the rabbit happily.
(3) A beautiful bed was at the back of the room. --> At the back of the room was a beautiful bed.
Sometimes, the verb comes after the fronted element. (In this case you can also talk about inversion.) In example (1), there is fronting with no inversion. In example (2), there is fronting with optional inversion. In example (3), there is fronting with obligatory inversion.