Gary also faced a very statist state legislature, where 2/3 of legislators were Democrats, and the 1/3 of the legislators who were Republicans were mostly big-government Republicans. Governors can't unilaterally slash government. Only the legislature can pass bills slashing government, and Governors can sign them into law. Governors can, however, using the veto pen, put the brakes on big government and prevent new big government legislation from coming into law. Gov. Johnson did just that -- in fact, he vetoed more bills than all the other 49 Governors in the country at that time combined. But he also did achieve a lot of positive results -- he got 14 tax cuts through the legislature, he was able to cut the size of state government by 1200 employees by managing attrition, when he left office he was one of only four Governors in the country who balanced their state budgets, he got significant welfare reform through the legislature, and he got entitlement reform through the legislature that cut state Medicaid spending by 25%. Also, his advocacy on issues like ending the War On Drugs shifted New Mexican opinions significantly, according to polls before and after Gov. Johnson began his anti-Drug War crusade. You might not think New Mexico is a libertarian paradise, but if you could see New Mexico after 8 years under any of the other gubernatorial candidates, compared to New Mexico after 8 years of Gov. Gary Johnson, I can guarantee you'd be able to see a VAST difference in terms of freedom and prosperity.
Furthermore, criticising Gov. Johnson for not having any success getting through to the legislature doesn't really fly as a way of promoting Ron Paul instead, who has spent decades in Congress being relegated to a dusty corner. Even in the height of his recent popularity, Ron Paul hasn't even been able to get a basic audit of the Fed implemented yet. I can't really think of any significant legislation that Paul has gotten passed or defeated. This isn't to knock Ron Paul -- it's just to point out how retarded it is to criticise Johnson for the same thing (especially since Johnson actually DOES have a handful of policy victories under his belt).