Is there any way to completely change your base around like in clash of clans where it removes everything from the screen and then you place the objects where you want them to be? Please help!
That is a fair question; and I have never played Clash of Clans. However, from what you described... I would say, not at the moment or at least not that I have found in the last 2 months of playing.
At the present, all building's remain permanently once built and have to be moved around manually. You can zoom in and out on the screen, which should help with base designing. For walls, I personally group them in strands of random lengths then break off and manipulate what I need.
I.E. I have a section of wall at 10 blocks length, and I need a section 4 blocks long. I simply count out 4 blocks, remove the 5th block then move that 5th block to the end of the strand; thereby leaving me with two strands (one at 4 blocks length and another at 6 blocks length for future use).
Hope this helps!