Depending how vivid your scarlet is: You can go with white or cream so it really is the accent wall and nothing is shouting for equal attention You can also go for a muted grey or beige

My drawing room front Window is going to be of around four feet wide. As the width of this room front wall is 10 feet out of which 3'6" will be kept for front entrance door. I am confused whether the sill height of the window should be 6 inches or 3 feet high as sofa is coming in front of it as my drawing room size is 10'0" * 14'0".

Srini, People have their respective likings and it may not meet your needs. If you have a requirement for an additional room then you go for it. If you have say 3-4 rooms already then a high ceiling living would be worthwhile. An open spacious living room is a big yes for me.

It's a good design and you can highlight the staircase wall too and go for designer celling in that too with chandelier see the reference image If you need 3d views and Interior Consultancy for you room pls contact us