A film should work within itself regardless of what Episode it is or something. ROTS is quite competent at establishing their relationship and what is it that falls apart - ditto for Anakin!s relationship to Padmé. Not a surprise it was reviewed more positively than all other Lucas SW films upon release - with the exception of the original.
Absolutely, I completely agree. The chase scene in Attack of the Clones, as well as the entire opening act of Revenge of the Sith, are completely dedicated to showing positive interactions between Anakin and Obi-Wan. I too think they could have included more moments like these, but some people act as if the two were constantly at odds throughout the Prequel Trilogy and never had any positive interaction — which just isn’t true. In the first half of Revenge of the Sith, they share plenty of good moments. Even when Obi-Wan tells Anakin that the Council has asked him to spy on Palpatine, he doesn’t blame him for anything and even apologizes to him later.