I think a Democrat president would very likely succeed in getting what he (or it) wants..
Why wouldn't a D president succeed in getting a more lenient amnesty? What track record of success does an R congress have with a D president?
Do you remember what happened in '95? Do you remember what happened in January and February of '99? And, those were the few and far between stand-up times. And, they both ended in failure. Yet your romanticize it.
I'll take my chances with the R president.