There's a difference between RHM and strongest commander.
Roger, Shanks, Kidd and Luffy can't fodderize their RHM like Roger and WB did to Oden
- Rayleigh is called Dark King
- Beckman enjoys the same fame as Shanks in contrast to the other crewmembers
- Kid calls Killer his partner and built the crew with him
- Zoro and Luffy share the same partnership as Roger and Rayleigh did, they even get called partners and people have mistaken him for the captain often enough
Oden was WBs strongest commander at that time since the rest were basically kids. Still there was a huge ass gap between the two. WB also never intended to have a strong independend RHM as he has bad experience with the rocks and he feared his authority endangered