Well, room treatment is necessary to get your equipment to sound the way they are designed to. You spent all of that money, you may as well get what you paid for. A dedicated listening room is up to you. I decided to go with it and am glad I did. I did away with home theater all together. I found that I didn't need to hear every detail of Hollywood soundtracks. But music that's another story.
Again your choice.
As far as room treatment don't waste too much money on it. Furniture or DIY absorbing/diffusing panels will do good enough if placed at first reflection points. Since you seem to have your echo problems under control then that's one less thing to worry about. If bass is tight. Don't worry about traps in the corners.
to sum up:
Do treat first reflection points (critical)
Treat Echo (critical) unless room eliminates naturally
Bass traps (critical) unless room eliminates naturally
other treatment is just tweaking
Don't overdampen a room either. It will sound as bad as an untreated room or worse.
Again your choice.
As far as room treatment don't waste too much money on it. Furniture or DIY absorbing/diffusing panels will do good enough if placed at first reflection points. Since you seem to have your echo problems under control then that's one less thing to worry about. If bass is tight. Don't worry about traps in the corners.
to sum up:
Do treat first reflection points (critical)
Treat Echo (critical) unless room eliminates naturally
Bass traps (critical) unless room eliminates naturally
other treatment is just tweaking
Don't overdampen a room either. It will sound as bad as an untreated room or worse.