Modern home plans come in all shapes, sizes and styles. It will be up to you to find the one that best suits your needs. If that's a contemporary plan that includes an open layout, you can find plenty of great plans available to choose from. Of course, you also have the option of creating your own home plans based on your requirements, be they extra bathrooms for the teens, home office or workout space. Perhaps you want an open kitchen and lounge area, but a private dining room. Maybe you prefer the entire lower level to be open but want the sleeping areas divided accordingly. It really doesn't matter because you can get whatever you want.
Although the traditional English style of cottage is most typical in America, cottages can be built in a variety of styles depending upon location and the builder's tastes, ranging from Spanish house floor plan designs of the Southwest, which typically have single stories, stucco exteriors, and tile roofs; to Cape Cod cottages which are usually box-like, timber-framed structures two-stories high, with steep roofs to shed rain and snow.
Given their professional experience in house designing, it can be helpful to hear why certain elements will and will not work as you may envision. Your architect will be able to show you 3D walk through plans too. This can be useful exercise to examine sun patterns at different times of day and get a feel for the scale of your future modern home.
Aesthetics is in the eye of the beholder, and it depends upon the prevailing tastes of the time. A building's functionality, or fitness, is a matter of how well it accommodates the purposes for which it was built. Its structural integrity means soundness - will the building last over time? Historically speaking aesthetics has usually trumped fitness as the overriding factor in architectural design. Classical architecture was preoccupied with articulating features on walls and facades. Modern architecture is equally concerned with aesthetic formalities, such as form following function.