Printable View
With innumerous blogs out there and so many great themes, a good blog design will definitely help a blog to stand out from the rest by making it easily recognizable and identifiable. This is one of the most important benefits of a custom theme. Once you have your readers gripped to you and they keep coming back to your for more information, they are less likely to pay attention to the design.
The last sentence in your post is in my opinion incorrect , while having a nice looking website can help ive seen many Ugly website that are just structured so well that they work. They are structures with users behaviour in mind and guiding to a conversion point , also themes are weak in this regard and even weaker in their seo ( for the most part. ) its something you have to go and change on most themes structurally. If you know what you are doing as a programmer this is ok, if you dont you try yoast which is a joke. Because while it may help with the superficial problems in your website its not going to help the the deeper internal issues , and how well your website actually sells... looks are not everything you will go have a look at your top serp results they are hardly ever the most visually appealing websites.
Its a kind of important factor
Kind of yes, but if you look at reality how many "ugly websites" are doing well because they are just easy to use for users its a very big percentage. Go look at the top 5 for most niches on google and you always find a good couple of websites that arent concerned with the latest animations, sliders and facy css tricks. Users know we can produce pretty websites, and they are starting to care less about that and more about getting to the point, good info and sale information. Google even knows this thats why it favours fast loading sites with less js. I have even read that it ( google ) is moving away from jquery. Minimilism in design is back for a reason , i read so many posts now that dont even recommend using a slider anymore ( with studies showig how not having a slider can decrease bouncerates on a website ). People want good info.
Blog's design is always important factor.