Common design would explain it just fine.
That's like saying "evolution would explain it just fine" without even saying what "evolution" is.
In this and other threads (and in millions of other sources) exactly
how evolution produces the observed results (like DNA relationships, fossil record and lab experiments).
So to offer "common design" as an alternative explanation we'd have to see the same level of details. How is the design done and implemented? How is the "design" reused to produced the observed results? Those and 10,000 other questions would need to be answered.