It sounds like you're moving towards a great room concept - where living, dining and kitchen are all open to one another. This concept wasn't generally a founding one for mid-century architecture - although I'm sure it has been done in renovations to great effect.

Laura makes a good point that it may not add value. The mid century is a vintage home and to many buyers will find the original foot print to be attractive. Besides, I wonder if there won't come a time when we move away from the open concept and return to interiors with some separation. It's nice to walk into a home and have a sense of discovery because everything isn't presented immediately.

With that said, you'll have to think about it carefully: continuity of materials, palette, organization and flow. Another option is to carve out niches for openness. Here's an example that I think works quite well:

Lots to consider...and plan plan plan. If you are redoing your kitchen, sometimes losing a wall limits cabinetry. Storage is always something to consider, especially if you may be selling your home a few yrs down the road. To a lesser extent, it can also limit furniture arrangement. Aside from talking to a designer, you might also consult a realtor who knows your area well.

I would say that it is common to see an opening in the kitchen to living space, but not completely open to it. Here is one example:

Here is a photo of a "mid-century" kitchen open to the dining, but I would need skates to cook along this long wall: Here is another kitchen that uses a peninsula to divide the spaces:

Good luck with whatever you decide.

What is the positioning of your rooms? For instance, is your dining room straight ahead of the kitchen with the living room to one side, spanning the length of kitchen and dining room. Do you have a fireplace in the living room. If so, is it on the wall you wish to remove?

Our home was built in 1978, it is a ranch style with a formal living room w/fireplace, you then walk into the 'back of the house' which is a long room with kitchen, dining area and smaller living area with fireplace. The fireplaces share the wall and are offset, completely separate. We have beautiful view in the rear of the house and never use the 'front' living area. As the back area is much smaller, I'm looking at opening the floor plan and having an open concept. thank you