I think if you lack risk tolerance, maybe you shouldn't be investing and thinking about early retirement. Even with a large bond percentage in a downturn, you're still going to be carrying 60-70% stocks. And you're still going to be seeing a stomach wrenching loss in your portfolio. And now, we're to believe that Mr Safetypants is going to move their precious bonds into stocks right at the moment when it seems like the whole world is on fire? When, like in the depths of 2008-2009, people were having serious discussions that Bank of America might go bankrupt?
And for bond lovers, that's usually the only case they can point out where bonds are worthwhile. Go look at the investment quilts. For that one year where bonds outperform stocks (and only because stocks did poorly, not because bonds did great or anything) you've got another nine years or so where bonds and cash are in an epic battle for dead last place.
The only time I can think to invest in bonds: when you've already got more money than you'll ever need. Why roll the dice at that point? And that's what people that are accumulating large bond portfolios are essentially doing. Working and paying taxes to the government longer in order accumulate more money then they will probably need. All done in service to the comforting warm blanket of lending your money back to the very same government. Crap, I almost sound Libertarian (I'm not by a long shot).
For yourself I'm sure everything you mention is excellent advice. As someone who was in 100% equities for most of my investing life I have no quarrel with the fact that equities, over a long time horizon, outperform non-equity assets. That said, every forum on investing is chock full of people who thought they were OK with whatever outsized asset allocation they had chosen, but discovered they could no longer sleep at night when their portfolio was suddenly worth half what it was a short time before. So they sell. They converted paper losses to real ones. I can't think of a better way to absolutely decimate long-term portfolio returns than this. In most cases where people fail to meet their investment goals, this is the reason why.
It's fine to say "if you lack risk tolerance, don't invest" but you are talking to a very large number of people who really MUST invest. Early retirement is a GOAL and no more. However, most everyone will need to replace their working income at some point, early retirement or not. Being invested in even a 50/50 portfolio, as abhorrent as it may be for you, will get an investor much farther than avoiding the market entirely. To get the best risk adjusted returns you only have to go to 60/40. For this "warm blanket" that investor forfeits 1.6 percent in average annual return (8.6 vs 10.2).
Another thing to note. Choosing when to ramp down from 100% stocks to non-equities isn't as easy as you make it sound. You can pick the age you think you want to do that, or choose the dollar value of your portfolio that you believe "is enough" but neither of those controls for market conditions. If you decide you want retire at 45, and you have to accumulate until you are 44, you hope the market is not down significantly or you run into sequence of returns issues. If your 100% equity portfolio is down 20 percent you probably aren't going to sell to re-allocate to bonds. Hopefully your dividends will be sufficient to cover your income, but that isn't a given. Hopefully its just a short downturn. So what to do then? Probably work longer.
Investing is about making money long term. Being successful has more to do with temperament and understanding your own limitations than strategy. Buying high and selling low is the exact opposite behavior we want to have as investors, but that behavior is found most often in those who misread their tolerance for risk, and who misunderstand their time horizon.