Here is a link to the Aikikai Hombu grading chart. It might help you get an idea of what to expect.
It sound like the dojo you are training at may not be the best fit for you. Does your group include any Kokamishin training? Have you brought your concerns to the head of your group?
Thanks for the link I will look at it when I have more time. As for my dojo I have mixed feelings - I in fact go to two Dentokan AJJ clubs, one on a wednesday and one on a friday. The reason I go to two is that both clubs only meet once a week and so for more regular training I go to both (as do many others including some of the instructors). The downside to this is that you get different sensei's teaching different things in different ways, which when you are training for a grading can be very confusing - Nihonage is a perfect example, they each have slightly different ways and preferances for how the technique should be performed.
The wednesday club used to be Nigel Goodier's club and he used to be head sensei there; he still teaches regularly but he has stepped down as head instructor. Nigel holds the rank of Hachidan-Kaiden and due to his close connection with Hobbs Sensei his instruction on kata is taken as gospel. I feel very privileged to be taught by Goodier sensei but as he no longer runs the club he's not there every week and is often travelling to instruct Dentokan clubs overseas. Personally I feel Nigel's approach is closest to that of Hobbs Sensei.
Something else that Nigel infact brought to my attention after my last grading was that here in the UK we are the only clubs within Dentokan who grade in both variations and kata. While Hobbs Sensei gave permission it was an innovation introduced by the Ipswich (East Coast) club. Since learning this I have had very mixed feelings about why we grade differently as our grading practice is split between kata, variations and knife defence. There are times when I feel one or all three suffer because of this. That is not to say I don't think variations are important - when I first began training it was the most exciting thing for me, but now I realize the importance of kata and mastering the form.
Neither of my two clubs practice Kokamishin-Ryu; from my knowledge only Lloyd Allum Kaiden Sensei of the Ipswich dojo teaches Kokamishin-Ryu and indeed the Ipswich dojo is the hombu for Kokamishin-Ryu in the UK. Hobbs Sensei came over to Ipswich last year and taught a seminar on Kokamishin-Ryu so I have some training in it but due to the fact that the Ipswich dojo is about 45-50 mins from my town I do not train there regularly, as it is I already commute to my two clubs, which are closer.
Regarding my concerns I have gently voiced some of them before, but I don't think anything will change. Our clubs seem to be too influenced by Ipswich to mirror those of the USA branch of Dentokan. The frustrating thing is that there are not that many Dentokan AJJ clubs in the UK, most of them are concentrated around East Anglia so I have very little choice if I want to continue with the art. As long as I am living here in the UK I definitely intend to carry on training in AJJ but I will probably convert to Aikido if I moved.
I am also very interested in Daito-Ryu AJJ and would potentially cross-train if it became a possibility, but I still think I would make Aikido my primary art in future.