We have DC-10-10s, DC-10-30s, MD-10-10s, and MD-10-30s.

MD-10-30s are not as nearly underpowered as the MD-10-10s, you are correct.

All MDs land slightly different in my opinion. Power, control surface size, and computer help in the MD-11 all play a part.

It's not hard, just different. All can be landed well.