The base changes the feel
Kansai looks compact, but Osaka and Kyoto create different mornings and evenings.
Kyoto as base
Choose Kyoto if several days need early temple starts, gardens, Arashiyama or a calmer rhythm.
Osaka as base
Choose Osaka if day trips lean toward Himeji, Kobe, Universal, food evenings or onward transport.
Let trips decide
Nara works from both. Himeji and Kobe lean Osaka. Kyoto temples and Arashiyama lean Kyoto.
Avoid extra hotel changes
With only a few Kansai nights, one strong base often beats a theoretically perfect split.