**Our American Constitution was promulgated in the late 18th century and continues to function with only a handful of updating amendments. Poland had 4 constitutions in the 20th century (7 if we include interim Little Constitutions).
This is uncomparable.... During this time, first Poland didn't existed, then existed as a multiethnic entity, then didn't existed again, then existed as a monoethnic communist dictaturship, and since 89' Poland is democratic republic. So it is not surprising that the law was changing contantly...
**Educational reform -> splitting highschools into two separate levels. In my opinion it was a mistake and unnecessary change, but it is hard to see politics in that. Gov. really thought it would be better system and they had some merits. Other than that and huge boom in private universities there wasn't any structural changes. So I wouldn't say it is constant change.
**Health care is not changing much, there was a try with those "Kasy Chorych" but it failed, and now we are back where we were for good and for bad.
**about tax'es I have mixed feelings. They are of course to high :-) Are they complicated, I'm not sure. My friend told me, that Polish base tax act has about a few dozen pages and British base tax act has about a few hundred pages. Judging from that it seems that Polish tax law could be more complicated ;-) So maybe it is not a problem with a law itself but with arbitrary execution of that law.