I lived through the Clinton impeachment issue, though I didn't pay much attention during his first presidential election. I favored impeachment at the time, as a Libertarian, based on a number of issues. Obviously, I felt that perjury (the most significant crime he was charged with) was something he was both obviously guilty of and serious enough to at least consider the impeachment process on its face. It boggles my mind that someone nominally on the Republican side who actually lived through that period would say that Bill Clinton didn't commit impeachable offenses. Perjury by government officials absolutely must be an impeachable offense. Why? Otherwise the President and his staff, or the judicial branch and theirs, can lie to Congress with impunity, making a mockery of oversight and public accountability, and blocking Congress and the courts from being able to do their job.
You can argue that it might be politically unwise to use lying about sex (and sexual harassment, under oath in court) as a reason for impeachment. But the crime of perjury is undeniably and necessarily impeachable.