"Bulky design" refers to something that is large, heavy, and takes up a lot of space. It usually implies that the object or item is not sleek or compact in its appearance or form. Full definition
However, some parents have regrets due to the often bulky designs of them and many opt for a combination of baby carrier and baby car seat instead. (mombible.com)
They, too, are a bit unusual, offering a much less bulky design than those used in other models. (articles.orlandosentinel.com)
If you can look past the somewhat bulky design, this running stroller can be yours for around $ 200. (earlymomentsmatter.org)