The main problem with direct payments is not technical, it's social. People use deposit addresses for closed exchanges (see MtGox) and sometimes lose or change wallets. The management overhead required to maintain these lists on behalf of users is substantial, and even if handled 100% correctly people sometimes forget to notify the issuer, or notify the issuer too late of changes. When a payment is then sent to such addresses (sendmany) it causes further problems of irrecoverable funds. Having a user be able to directly specify a withdrawal address on a platform, then request that payout directly removes this problem.
I don't see what "management overhead" is required to have a list of addresses... But regardless, if you're so worried about shareholders "changing wallets" without notifying you, you can make it a matter of choice. Shareholders who refuse to register to cryptomex could opt-in to receive their dividends using sendmany, and if we lose the relevant private keys that's our own problem.
If you refuse to allow this, the only other option is a buyback at IPO price.
