For the last ten years it's been a latte brown/grey, okay greige, 3 seater. I'm loathed to get rid of it as it still is so comfy, though somewhat worn and faded. Desperately trying to the find a drill, cotton or linen in a bright teal/ kingfisher/ peacock blue to re-cover. Something like this...

Of course its all about how your going to be using it and the layout. If you cozy up with a pet, human or animal, how that will play out. Are you watching TV or a fireplace or both. Think about windows and how they will reflect onto the TV at different times of the day. Is it a space you read in or play games etc. Also, children and pets or partners grubby socks, does it need cleaning all the time or be stain resistant. Comfort of course plays a huge role or you won't want to use the space. I would think on those things first. Remember its a big purchase and should be in a neutral color, I always gravitate toward a grey or dark leather, to ground the space and liven it up with texture and color by pillows and throws. Good luck

I can understand the frustration at the thought of obscuring the sliding doors. To avoid that you might consider a pair of sofas that face each other. (Like in the picture attached) This position looks very welcoming as it invites the seated people to face each other for conversation. It does mean for viewing the tv on the 'blank wall' you won't be in the most comfortable position, so I suspect you'll need to compromise somewhere... Access to the door against tv viewing.

What are the dimensions of the room. The lounge pictures look too bulky for the space. But your lounge room photo might be deceptive. That's why measurements of room would help.