Hard Forks are perhaps one of the most difficult decisions a DAC must make for anything other than a bug fix. The code represents the "constitution" and generally speaking a hard fork should require more than 51% of shareholder approval. Unfortunately it is very hard to get that kind of consensus.
Discussions on the voting thread have shown some advanced market-based approaches to voting that could help the community come to a more "fair" hard for decision with greater than 75% approval by creating a market for votes on particular hard forks.
1) Every shareholder gets a vote and can be in one of 3 states: Yes, No, or "Accept Majority".
2) Every shareholder may sell their right to vote on a particular issue without selling their underlying BTS.
3) Once you get 51% turnout and 75% consensus a hard fork is activated... (it must already be implemented prior to the vote, just contingent on the vote for enabling it).
What this means: those who might be negatively impacted by a hard fork and thus vote "NO" can get compensated by those who would be positively impacted by the hard fork by selling their No vote to them for more BTS. It also means that those who might not "care" will sell their vote to the highest bidder.
So the process for implementing a non-bug-fix hard fork would be:
1) Discuss on forums and get general consensus that it is a good idea
2) Have developers implement it
3) Have delegates upgrade to nodes that support it
4) Have shareholders vote to enable it
As long as this process is in place then the DAC can remain flexible while having "hard coded" limits on dilution that can be changed without violating the consensus with super majority vote.