I'd have voted Dale Murphy. Unlike many longevity guys, he wasn't great till age 24 or after 31. But during the 8-year prime, he was so great. Prime WAR's of 6.6, 6.1, 7.1, 5.5, 5.0, 7.7. So in 8 seasons had six with WAR ≥5, back-to-back well-deserved MVP's, five straight gold-gloves at premium defensive positions, twice-HR champion. Man was his prime great.