I don't really think that raising the requirements would change anything. Those who view this as an amnesty will continue to view this as one even if the beneficiaries of this bill could never become full citizens (and thus not be able to bring others with them) or even if they had to pay exorbitant fines or perform excessive community and/or military service.

The number of people who will be swayed by additional requirement is so limited that it's much better to just focus on getting people to support the idea of the act as a whole.

Besides, all of those additional requirements will probably hurt more than they would help. Requiring military service from dreamers would balloon the military by several hundred thousand to a million more people; considering how they're actually trying to slowly cut back and demobilize parts of the military, this is not doable. Requiring dreamers to pay out of state tuition is also not doable because a) tuition requirements are decided on a per-state level, b) it's extremely difficult and rather unreasonable to ask someone to pay $8k/semester+ for tuition. That will help neither the dreamers nor the college. After all, the educational system is there to help the people going through the system as it is to help the community and the economy as a whole.

I would personally raise the entry-level bar to just under 18 years of age and then keep the rest of the bill the same.