I am aware of the recent trends that are going in practice but whats the impact of it to the users. In recent years designers have been using big search field and the navigation bars have been increased respectively. Usually we can see block lists rather than inline lists for the navigation. How does this big search field and block list for navigation makes an positive impact to the user? I have attached an image of the recent trend that have been used in one of the template.
Yes, true. from user experience point of view the large 'Search Block' gives user enough space to use the appropriate words for the search , also screens differ from smaller phones to big screens so giving a user broad area to enter its search and making it provident enough to surf through your product page. [since grids differ screen wise] Menu again follow is one of the important feature for retail oriented sites where need to emphasize more on attracting user's attention towards their 'Menu' & emphasizing them to explore more and in a convenient manner. Again, Views change for Menu from Mobiles to desktops. Also gives a neat look , less is good, desirable. This is my point of view on using large menu bar and bigger search bar.
I think the decision to prioritize site search is directly tied to it outperforming traditional navigation schemes in both user experience and bottom-line conversion rates. Keep in mind I do not believe that every big search box was a data-driven decision on behalf of the designer - but I do think this is where it originated.
This is especially true when deploying rich search interfaces that go beyond simple type ahead and try to expose results as the user types. Example from Home Depot:
Many sites have also employed faceted navigation (also called "dynamic navigation" or "faceted search" to provide users with the ability to filter results after the query is provided. This is the best of both worlds because it crafts a navigation scheme on-the-fly specific to what the user is looking for. Imagine the difference of exploring the full Home Depot site map versus just the departments or products relevant to what you are looking for. BestBuy is a solid example of this. Notice how the left filtering options change for different product families: