There is no such a thing as a transitional from the chimp-human common ancestor, it jumps from a profoundly chimpanzee Homo habilis to Homo erectus over night about 2 million years ago.
Neither of them are "profoundly chimpanzee". You'd think you could infer that by the fact that they were similar enough to us to be put in the same genus as us.
chimp skull
https://cdn.shopify.com/s/files/1/1467/6660/products/BC-003_Chimpanzee-x4.jpg?v=1509395068
Homo erectus skull
http://www.anatomicalproducts.com/i...b400x400/dfc72cb180b058076ea930345785db21.jpg
Homo habilis skull
https://boneclones.com/images/store-product/product-1591-main-original-1415043897.jpg
Yet for a million years starting about 3 million years ago you have paranthropos which is an obvious transitional somewhere between the gorilla and chimpanzee.
Hahahahahahahahahahaha, members of that genus were hominins, which excludes gorillas. Heck, it's uncertain if chimpanzees should be included in that or not, but regardless, no member of the Paranthropos genus is a gorilla ancestor. The shared lineage of chimps and gorillas diverged BEFORE the shared lineage of humans and chimps.
Genomic comparisons map the essential changes required and they are extensive. Brain related genes would have to be built from the ground up and hundreds of millions of stasis in other brain related genes would have had to be radically altered.
-_- hundreds of millions? Dude, humans don't even have 30,000 genes, what the heck are you talking about? Also, justify why any human brain genes would have had to have been "built from the ground up" when most of the brain related genes in humans are the same as those in chimps, and the most relevant differences are gene losses on our part.
What is far more telling is that there are no chimpanzee fossils in the fossil record, if they were not alive to day there would be no proof they ever existed.
-_- first chimp fossil was discovered in 2005, but all of us are well aware that it is likely the majority of life that has ever lived on this planet has never left behind any fossils and is thus lost to time. Our lineage is actually fortunate; human ancestors happened to live in areas that were great for fossil formation. Chimp ancestors, not so much, but to act as if there are no transitional fossils for them, or even fossils of that species, when just 1 quick Google search demonstrates otherwise, doesn't make you look good.
The human brain is almost three times bigger then a chimpanzee and the brain matter is nearly twice as dense.
-_- and I am taller than my sister. More of something is one of the most trivial forms of variation in a population, especially if it doesn't disrupt bilateral symmetry. Heck, human variation in intelligence spans from immense genius to people so stupid I wouldn't be shocked if they forgot to breathe from time to time.