If you were chosen to develop an element we use daily,what will you choose and what is the part that is going to change?

As a designer I'd like to keep my ideas to myself, you've asked a very broad question, one that takes weeks to sort and figure. Likewise no designer would let out their target artifact. However, i'll give you a hint on how to figure out, use the element and constantly look for flaws and gaps in the usage, be as optimistic as you can. That will help you figure out what to develop.