If we're being honest and I've said this before, if not for the logia property. Oven has a stronger fruit than Akainu. Oven controls temperature itself and can heat things up as he sees fit and god knows how high those temps can go, I'm assuming the hottest in the verse since he has complete control over it.
However being a logia is just too big of an advantage. Producing an element of the highest class at will, and turning into it gives it too much separation. If it were a flame logia maybe it's a closer discussion, but the magma element is innately strong enough where not having complete control over temps isn't a big enough issue.