The term "more extendable" can be replaced with a number of synonyms, depending on the context of usage. For instance, "more adaptable" can be aptly used to describe a software program that can easily be modified. If you are referring to something that can be stretched or expanded, "more elastic" may be a better choice. "More versatile" works well when referring to a tool or machine that can be used in multiple ways. Similarly, "more malleable" can be used to describe something that can be reshaped or molded without breaking. Overall, when seeking alternatives to the phrase "more extendable," it is important to consider the specific meaning you want to convey.