I've been saying this since basically after Obama was elected.
I was a HUGE supporter of his, even in the democratic primaries. I donated to him, I was running local groups that were canvassing and phone banking to get him elected. I was ecstatic when he got elected (though I viewed it as a foregone conclusion, I didn't think McCain had a chance).
When it came to the governing, I was not really impressed. Basically from day 1, everything seemed stuck. He got a few things done (ACA though that's of dubious benefit, and was done in such a way that it became a political punching bag and can't get any reforms), but mostly in the first two years. After the 2010 midterms, this shit was just complete gridlock. You can blame whomever you want for the gridlock but a good leader builds compromise and ends gridlock.
I think there are two good examples of this. First, after sandy hook Obama promised that he would pass gun control legislation. Now, I do not agree with lots of things that he would like to do with such legislation, but, I do agree that there are some changes required. He has basically failed to pass any legislation around gun control and his response to that isn't to propose new legislation that can pass congress. His reaction was to go on national television and cry (literally) about his failure to pass gun control legislation.
I'm sorry, I don't want a damn leader who CRYS about their political failures. I know dead children is a sad subject, but, this is ultimately a political failure.
The 2nd one is Guantanamo. When he was campaigning one of his promises was to close Guantanamo, bring prisoners home and try them for their crimes. After 8 years, that has not happened and its become so politically untenable that he's basically letting these people out, without trying them at all. It is a mind-boggling
Withdrawing from Iraq/Afghanistan was another campaign promise that I was personally invested in too, but that is a far more complex one and though he doesn't get a pass from me on that as I have personal losses there, I acknowledge that its more complex.
I do not agree with lots of things that (old) republicans did (though I am hopeful about the new republican party of today), but they get shit done. They wanted to block (stupid) gun control legislation, they did. They wanted to block returning Guantanamo prisoners to the USA, they did.
Sometimes doing something, even if its not perfect, is more important than doing nothing, especially when you don't have a crystal ball and don't know what exact result specific actions/legislation will have. Move fast, break shit.