Of course they must, and I am definitely not suggesting that people should be frivolous with their cryptocurrency by using exchanges that show red flags, with the idea that they will be recovered. This is definitely not the case. Not your keys, Not your coins is something everyone should still have in their minds when transacting, trading and storing any cryptocurrency.
I agree with you about risk of centralized exchanges if people store their cryptocurrencies on those platforms.
They must read and watch these ones
Reminder: do not keep your money in online accountsBitcoin Q&A: Not your Keys, Not your CoinsThe reality is that most exchanges are gone and will never come back, however it is curiosity that leads to think that if Mt. Gox can lead to the recovery of such a large portion of lost funds, maybe the recovery of others will follow suit. Mt. Gox is a very strong precedent that might enable a backlog of investigations and recoveries at the end of the day...It's entirely possible at any point following the success of the Mt. Gox recovery (possible doesn't mean that it will happen though, it just means that the precedent could enable this).
Exchanges are dead for years and can have money to pay their past customers are very rare. Honestly, if I am a victim of Mt.Gox and receive compensation from them this way, I would feel very sadly and disappointed, first about myself to make mistake by storing bitcoin on Mt.Gox. Second, it will like another unnecessary scratch on my wound which I forgot for years.
$200 or $1000 is big money but if receiving it causes me to regret that if I had not made that mistake, I would be a billionaire now, it is very painful.