John Borowicz has high hopes that a new state-run health insurance exchange will make buying coverage simpler and more affordable for his Plymouth-based business. When he and his wife, Jackie Drury, bought Ovation Framing a year and a half ago, Borowicz set out on his own to find a good health plan for his six employees. It brought nothing but frustration. "It was near impossible," said Borowicz, who previously worked in corporate IT. "It's a Byzantine and stupid system that doesn't make any sense." Signed into law Wednesday by Gov. Mark Dayton, the exchange will represent a fundamental change in the health insurance marketplace for small businesses and for people who don't get health coverage at work.