The similarities between Jones and Lesnar are undeniable; groundfighters, poor striking, not long training MMA, biggest fighters in their divisions without being slow, lots and lots of hype.
I don't like Jones' chances against Rua but win or lose he's going to be/already is a big concern in MMA and will improve massively. This is where he differs from Lesnar, who seems to be too involved with the business side of things and doesn't actually spar in training.
On topic though, Jones really could have done with fighting a current or past Top 5 fighter before the title shot, but all the other fighter's situations combined makes him the best option right now. Some good hard Brazillian leg kicks will do him good before he gets too ahead of himself anyway.