I'm a little surprised that they're only firing 336 people. Unless this is just the first round of layoffs and more will follow once products and management has been streamlined/trimmed whatever you want to call it.
That's a long way of saying I doubt there are more layoffs planned. That's not to say they won't make more layoffs if they don't get their shit together.
Since this is their first round, it probably consists of an accumulated RIF list that's been made up mentally over time by each manager, containing the slackers, bums, obnoxious misfits, and anyone absurdly overpaid, as well as people who have made powerful enemies. It probably also contains people who were working on canceled projects and weren't valuable enough that another manager would fight to have them transferred instead (some may be rehired by others later anyway). Standard stuff. And as such, since Twitter hasn't come to Jesus at this point, it's a pretty small round. Later, when it becomes apparent that more of what they're doing is a drain on their very limited revenue with little or no realistic hope of any return on investment, there will be more rounds as more projects are canceled. Of course, by then, they'll have less cash available and so will need to cut even more...
Every company in a downward spiral starts by cutting fat, then muscle, and finally bone. You're correct that it's much better to cut too deep the first time and stabilize the company financially at a much smaller size before cautiously expanding, but no one does it that way. Remember, to a manager, the size of one's empire is the size of one's dick (not to mention current and future pay), and to a CEO it's the same with the size of the company. No one wants to cut more than the minimum that can possibly be justified at any given moment, which is why almost every company that cuts keeps cutting in a downward spiral until sale or bankruptcy... and thus why there's always another round, as every veteran knows.
Really nothing to see here at all.
10% is a high number, but not for a company that has never made a profit and is currently hemorrhaging money.