Rayleigh was already likely Yonko tier via-scaling, so I'd say WB Pirates + Oden would still be an even match for the Roger Pirates. Aside from WB and Oden, you have 3 fleet commanders (maybe 4 considering implications on Thatch's power) being just below Admiral tier and the rest being far below them, so Gaban could still easily be around Admiral tier or between that and Yonko tier. I wouldn't fully agree on the idea of WB's crew being more balanced when considering Curiel not oneshotting or severely damaging Base Moria at Marineford suggests that outside of the likes of Marco, Jozu and Vista, most of the WB Commanders aren't what they're hyped up to be by New World standards, and keep in mind each of them may have been even weaker or less skilled back then.