I guess it depends somewhat on which market = symbol is addressed. The Russell 2000 (TF) emini is dramatically different now than circa 2008. There wasn't nearly the amount of algo domination then versus now. Having been my specialty for years, the difference now is profound. Other symbols, probably lesser. The big difference with ES now is seeing 100s on contracts depth per strike on the dome versus 1,000s flashed in the past. The epic swings are fun and definitely a most welcome change from those all-day, comatose 8pt total ranges. But traders can make as much or even much more money inside sessions with 1/5th the price movement of yesterday.
Always wondered how one can trade that freaking freakish ES You are risking to get Parkinson's disease.
I am looking at all liquid future markets. Equities (US, Asia, Europe), commodities (oil, gas, gold, corn etc), currencies and bonds. The daily ranges and sharp turns with big hourly candles in both directions are very similar. I see little difference across the board vs Oct/Nov/Dec 2008. 1930/31 markets would open up 8% only to close down 3% and vice versa. No program trading, no algos, no HFT back then.
There is a big difference between looking back at static bars on a chart, and seeing it in color from inside, trading bar by bar live at the time. The speed at which price moves = turns now is more abrupt than any other point in history. Ranges are one thing, speed of execution and movement is quite another.
In 2008, you could get size on at the top/bottom of moves, and if you were wrong you could get out with a relatively small loss. In today's HFT market, to get size you have to be early and be out of the money (no other way to get size on these V moves), and if you're wrong there is absolutely no way to get out without getting stomped. Anyone who moves size and says this is just like 2008 is lying. The risk is much much greater than 2008.