Stat Merging
Strength and Constitution are now one stat. You can rename it to Body or something, or just call it Strength.
Anything that references Constitution is simply replaced with Strength now. The exception to this is any class that gets Strength and Constitution saving throws-they now get Strength saves and one other of their choice. (The only official classes this affects are Barbarians and Fighters-and I'm okay with buffing their defenses slightly via better saves.)

HP Adjustments
With Constitution no longer existing, your PCs might be feeling fragile-but fear not! Instead of adding your Constitution Modifier to HP each level, you instead add your Proficiency Bonus. Additionally, you add your Strength Score (not modifier) to your HP once.
This results in significantly sturdier PCs at level one, with the lowest HP total possible in Standard Array being 16, on a Wizard or Sorcerer with 8 Strength.
At mid and high levels, it doesn't affect the overall total much for PCs that would have a high Constitution, but is a nice little durability buff to those who would have it lower.

Point Buy and Standard Array Tweaks
I don't use them anymore, but I'd drop Point Buy to 23 and Standard Array to 15 14 12 10 8.
These are both just off-the-cuff gut instinct adjustments. If someone wants to do math and find better totals, lemme know. :)