From an OB standpoint, the Peninsular campaign is obviously very complicated, with generals on both sides being added, then withdrawn, then added back. One obviously missing general on the French side is Lannes, who comes with Napoleon as a kind of wing commander in 1808 (maybe give the French another army HQ?). He won the battle of Tudela on 23 Nov. 1808 and he conquered Saragossa, which fell to him in Feb 1809.
British Gen Moore does not arrive at all. Historically he arrives in Oct 1808 and is later killed in the battle of La Coruna, and is so succeeded by Wellesley. In the game, if Moore isn't killed, there should be no Wellesely since historically Wellesley wouldn't get command if Moore was still around, unless the coalition surrenders a lot of VP to replace Moore.
In the spring of 1809, the French withdrew a lot of troops and generals to fight the Austrians. These generals should be withdrawn from Spain in April 1809: Bessieres, Lefebvre, Grouchy, Reynier, Kellerman, Berthier, Dorsenne, Grandjean, Lasalle, Lecchi, Severoli, Baraguay d'Hilliers - just reconcile the OB with the 1809 scenario.