Large room acoustics - thoughts on taming echo?

I just moved house and my new living room is 18x30 that extends in to an open kitchen with another 15' -- the ceiling are 18feet too!  

I've hardwood floors and relatively minimal furniture, a large rug in the seating area approximatley midway in the room with windows and french door along one of the long walls.  I've art and four foam/rockwool 2'x4' on the end wall as it lowers to the kitchen area.

I'm contemplating full height and width (18'x18') wood slats (1"x3" end on) with felt underlay on the front wall - behind the speakers both as a visual feature and in the hope of taming the echo/boominess of the room?

Will it work and/or is there something else I should do?  It's a living room and not a listening room and does need to be somewhat socially acceptable!

My system comprises Roon/NUC w LPS - Devialet D440 - Magico S5 - JL Audio F112