1)
Why is this "Ra'ah Gedolah Al Nafshoseichem"?
1.
Malbim: Now, the anger will not be exhausted on wood and rocks, like until now, rather, on souls.
2)
What is the significance of "l'Vilti Hosir Lachem She'eris"?
1.
Malbim: Initially, at least there was a remnant. Now, there will not be!