What if Lincoln had run on immediately ending slavery, pro mixed-race marriage, pro integrated...

...military and police forces, pro integrated schools, etc.?

Those are worthy and necessary goals. Anything less is immoral. That's completely true. I understand the disgust with accepting anything less. Every moment that a slave remained a slave was a tragedy. Every moment African Americans were denied equal standing in society was a grave injustice.

Nevertheless, the only way any of that eventually happened was in slow steps. The hellfire anti-slavery Lincoln I imagine never would have come close to winning the presidency, or yielding any sort of significant political power at all. Lincoln only ran against the spread of slavery beyond where it already existed, not for it's immediate cessation. Emancipation came only as a strategic move in the war with the South. I'm pretty sure Lincoln would have been shocked by blacks marrying whites. By modern standards, Lincoln would likely be considered a bigot.

That made him the right man for the job at the time. Just ahead of the curve of the American public, and not so far ahead that no one would follow.

There are times when too much patience is wrong, when waiting for tomorrow has got to stop. What's difficult is knowing when patience is a virtue and when patience is a vice. It's always more complicated that simply knowing what's right.