Designer and speaker Stephen Hay:
Emulation is a part of the evolution of design. And the web, for that matter. But design sameness tends to fade when one forgets all of the existing patterns, all of the Bootstraps, all of the preconceived design solutions. Design sameness fades when designers stop focusing on which solutions for their problem are out there and start focusing on the problem at hand.
Solve that problem, and maybe the solution is exactly what your peer implemented, in the exact same way. But maybe not.