I have no idea why people compare Perry to Reagan. Reagan cahnged his party after he travelled the US meeting with business owners, executives, and people who worked in factories as part of his job. He could tell you exactly why he changed and did so at a time when it wasn't exactly politically adventageous for him to do so.
None of these things have anything to do with Perry. Sure he was a conservative democrat, yet he can't explain or at least hasn't why he's such a big conservative or why that's a good thing other than the political tide turned in TX and that was politically adventageous for him to do.
I wouldn't be so critical of the issue having lived in TX and knowing that you couldn't get elected as a republican as many counties didn't even have republican primaries, except it fits with a lot of the other stuff he does. Like others have mentioned - he triangulates except on one or two issues. If it's popular today that's where he comes down, if it's not popular tomorrow that's the side he is on.