No political office within the whole of the United States government should be held for more than one term. This would strongly reduce corruption and illegalities because there would only be enough time for these individuals to focus on the proper management and interworkings within their respective job descriptions. Also no large entities and only singular persons may contribute to a campaign within the whole of the United States government. This along with a cap on the dollar amount one may contribute and a cap on the dollar amount one person running for office may accrue.
There are as many arguments against term limits as there are for, a main one being that why should you fire people for being experienced. My view is it seems more practical to simply get trustworthy people to begin with. A crook in term limits is still going to rob you, he'll just do it quicker
Even if some were incorruptible, the voters would not be able to identify them. So reducing the potential for corruption would be an improvement. I don't think that has a lot to do with term limits, but rather campaign finance. Term limits would just make them less competent.
The voters could assess after the first term if performances are commendable or not. I think the rationale behind is to curtail services of the incompetent and prolong for those who are deserving with public trust and confidence.
I agree with you about the need for term limits, but I disagree with a single one. I think 12 years in any Congressional office is a good amount--2 senate terms or 6 house terms.