Warren Buffett wants to buy more businesses to add to Berkshire Hathaway Inc’s “sprawl,” but cautioned it may not keep the company he has run for 50 years from evolving into something rarely used to describe it up until now: average. In his annual letter to shareholders, Buffett on Saturday said Berkshire’s huge balance sheet gives him the power to funnel capital to some of the more than 80 operating units that deserve it, while its decentralized structure makes it the “home of choice” for many businesses looking to sell.