I mean I don't want him to run again due to age reasons and the fact that I'd want someone who kind of fits in that ideological axis but is younger, but I'd support him 100% if he did. I assume a lot of people think the same way.
The thing is, Sanders' ideological wing of the party will probably be as divided as the Clinton faction. Warren, Franken, Brown, Merkley, Murphy, and even Harris would all be able to rip some parts of the coalition that gave Sanders 43% of the primary last year. All of those people are younger than him, so I don't know what decision you'd make if he isn't the only candidate that occupies the space in the Democratic Party that suits you. I'm sure this is a dilemma a lot of people with similar views as you will face.
Bernie really needs to run so that the only progressive candidate isn't someone the media completely ignores while having to raise a ton of money to compete in California and all of the extra states that decide to go early.