Mention the phrase “term limits”, and people will often consider advantages of term limits before they consider the disadvantages. It’s not surprising that when one relatively small state has a lawmaker who has been in Congress so long he’s almost fossilized, and this lawmaker has it made on the seniority gravy train for earmarks and perks to his state, others might think “gee — maybe we could level the playing field here”.
However, as this article states, having a bunch of non-career representation would reduce collegial relationships, cause even more “pledges” signed by lawmakers (effectively reducing their ability to get anything done), and make lawmakers far more susceptible to lobbyists and special interests. Congress would become a playing field for corporate interests, using lawmakers like little board game pieces.
One of the things that could be done to make it easier to replace lawmakers who need to be replaced is to do away with Citizens United. When incumbents build huge campaign war chests filled with money from interests they are beholden to, it’s difficult for a challenger to have a chance.