Bringing your kitchen into the modern era often requires changing the look feel and actual space. Updating is much more than replacing the cabinets. To conform with the "open floor plan" you may need to remove walls, window, doors and plumbing. The concept includes the idea that working in the kitchen does not shut that person off from the conversation or activities in the other room. Moreover, Mom's can work in the kitchen while the little ones play in the next room and are not under fot.
If the kitchen is small claustrophobic or odd shaped expanding it at least to the eye is crucial. By removing a wall to the dining room or great room you open up the space. Often I replace the wall with an island accomplishing the same separation in the same given space. The result however is an open look that is light and airy.
My goal in any kitchen remodel is to substantially increase counter space and maximize the number of drawers. Often I can accomplish these goals and more with an island. Need a more cabinet space, breakfast bar, extra sink or cook top, the island may be the ideal locations.
Decorating for the "open look" generally means that the style of the 2 adjacent rooms should be similar or complementary, though not necessarily identical. Natural light from one area should necessary flow to the other. Use color to accent or blend the two rooms into a singular use. Adding windows, patio or French Doors is a great way to increase natural light.
Cutting an opening in a wall or "pass thru" has utilitarian advantages but generally does not lead to the open look we are discussing. Removing a wall requires knowledge and planning. If the wall is "bearing" meaning the house is supported by that wall; it is imperative that you consult an engineer before you begin. In most cases a wall can be removed but the cost and ramifications can be extensive.
Finally removing a wall will affect both the floor and the ceiling. It may force you to replace the flooring and patch or redo the ceiling. Don't forget the electrician! Among other upgrades; plugs near a sink need to be GFI's, pendant or ceiling lights are great over the island, by code the island itself needs a plug.