you are mostly right. However the issue I have with your assessment is that you are saying "she had this this this this and this stacked against her, and the DNC made some huge mistakes"
The problem is EXACTLY AND PRECISELY what those huge mistakes were. They called her a criminal and she did nothing to respond to that. They called her crooked and irresponsible and she did little to respond to that. She made mistakes, many, over the years and the opposition made that the target of their character assassination.. and she never addressed it. Why? Well.. we don't know. Maybe she thought it was taking the high road by not playing their game? Maybe it was hubris thinking she still had the election even with that stuff out there (thanks to HORRIBLE polling)?
Whatever the reason.. those huge mistakes the DNC made was essentially ignoring the attacks on her by the other party, and the other voters, and just going on with her message as usual.
Who knows what the DNC will be up against in 2018. I "hope" (honestly) that we aren't up against an absolutely failed and abysmal GOP platform... because that would mean that much of america's life will suck for the next two years. However.. if we are.. then at least that gives them a little more leeway in who they can run with.
The better hope is that America isn't totally fucked in 2018.. but has enough frustrating GOP rollbacks and regression, and the DNC has strong enough, non-establishment candidates who can get the voters excited.
Polling (uggh...) shows that in fact most of the country typically does not want to see roll backs on social and environmental policies. Remember that only 27% of the voting population voted trump into office. Most social and environmental issues show anywhere from slight majority favorability, to large majority favorability. Get a candaidate that charges up Dems and moderates alike and a strong GOP platform over the next two years should be easy to topple. But the DNC has to NOT do business as usual.
about the worst that can be said.. is that the Senate likely won't go blue until 2022 at the absolute earliest. It seems this cycle is the one that contains the most battleground seats. 2018 looks to be hard red, and 2020 looks to be hard blue.