I sure do agree with that.
I don't think so. 16th and 17th for darn sure. They were part of the terrible trio of the 1909 to 1919 (counting Congressional passage to ratification of each) but the 18th was already repealed. I think most of the rest, save maybe the 24th (No poll tax allowed for elections to federal office) and 26th (18 year old voting in federal elections) are mostly postitive, and mostly concern only properly federal matters, such as Presidential term limits (22nd) and dates of taking office (20th). The 19th, 24th and 26th (and 15th) which all concern who can vote, can be seen as weakening federalism, since prior to their enactment the states set voter qualifications, but can also be seen as protecting or extending the rights of citizens, (15th the "out" races, 19th women, 24th the poor, 26th 18-20 year olds). the 24th and 26th only affect federal elections so I shoudn't say they weakened federalism either.
Amendment XVI [Income Tax (1913)]
Amendment XVII [Election of Senators (1913)
Amendment XVIII [Prohibition (1919)]
Amendment XIX [Women's Right to Vote (1920)
Amendment XX [Presidential Term and Succession (1933)]
Amendment XXI [Repeal of Prohibition (1933)]
Amendment XXII [Two Term Limit on President (1951)]
Amendment XXIII [Presidential Vote in D.C. (1961)]
Amendment XXIV [Poll Tax (1964)]
Amendment XXV [Presidential Succession (1967)]
Amendment XXVI [Right to Vote at Age 18 (1971)]
Amendment XXVII [Compensation of Members of Congress (1992)]