Obviously there are other requests, but the one about rank is the interesting.
Ego; ambition.
Grant wasnt expected to show up at either. Did Rosecrans need the supervision?
Regarding Rosecrans request that his rank be back dated to 1861, Halleck had written him in march 1863 :
"last summer, at your request, I urged the government to promote you for success in the field, and, again at your request, urged that your commission be dated back to your services in West Virginia". [Official Records, Series 1 - Volume 23 (Part II), page 138] Halleck was apparently lobbying to get Rosecrans promoted long before Iuka and Corinth.
In September 1862, when Rosecrans learned he had at last been promoted to Major General, instead of appreciation, he complained about it to Halleck:
"If fighting successful battles having important results; if successfully defending a mountainous country against an active and powerful foe; if pacifying and restoring law and order to a vast region with 300 miles of mountain frontier, and the successful administration of a department deserved anything from the hands of the Government it deserved my promotion from the date of the close of those services crowned with success. But what do I find? Why, I find myself promoted junior to men who have not rendered a tithe of the services nor had a tithe of the success. I find myself ordered from the command of an army whose confidence I possess -- a separate army in the field to go and take subordinate position in a new and unformed one, where Buell, Granger, Gilbert, Schenck, Lew. Wallace, Tom Crittenden, and Bully Nelson are my seniors. Were it not a crisis for the country I would not trouble you to intercede in my behalf but would at once resign. As it is a crisis I beg you to intercede for me, that some measure of justice may be done me. If I have deserved anything for my services in Western Virginia my rank should date from the close of those services, and that is what I ask in the name of justice. "[Official Records, Series 1 - Volume 17 (Part II), page 239]
To me, he come across as a whiner.