I disagree. If impeachment put the opposition party in power, then the incentive for impeachment would be much too high. The president would be impeached any time there is a larg-ish majority of the opposition party. Obama would have been impeached by 2011. Impeachment is rare because the political risk for those seeking impeachment is largely commensurate to the reward of removing the current person from office.
If impeachment worked in that way, it wouldn't be balanced, Congress would effectively choose the president, and impeachment would be an overthrow of the executive instead of a censure of the acting president. Most presidents would have 2-year shelf lifes, as historically congress swings against the president in his/her first off-cycle election. Further, in practice, many presidential losers are largely out of politics after losing. After Romney lost in 2012, having lost basically two presidential elections in a row (2008 primary, 2012 general), he basically retired from active politics. Sure, he gave some speeches, made appearances, had some interviews, but he was out of the national political landscape. It wouldn't make sense, in 2015, if Obama were impeached by an activist Republican congress that Romney would suddenly be thrust into the White House with a 16 month term... Or, Paul Ryan would suddenly ascend from the current Speaker of the House to being Vice President, and then his seat would be vacated, and congress would be in disarray in having to choose a new Speaker. Likewise, let's say Trump is impeached in 2020, Clinton might very well be mostly retired from active politics, much like Romney has been (as Clinton likewise basically lost two elections -- 2008 in the primary and 2016). There is a pattern here. When Gore lost in 2000, he mostly bowed out of the elected political scene and focused on activism and not politics... He really was reborn as an activist for big, global and national issues, which is wholely different than how he was perceived as a Vice President. Consider also that the president is not just the executive at signing legislation, but also -- technically -- the Commander in Chief, the highest position in the US military. The affect on active military to have what could be a reverse-course in the midst of some military action, because of domestic political battles at home, would be disorienting and potentially dangerous.
The framers of the constitution knew that impeachment is ultimately a bad thing, it's not something that you should want, and it should only be undertaken when the center of impeachment is worse than the process and result of impeachment... WHich, in Trump's case, I'd argue a Trump presidency is worse than the bad result of impeachment.
