[@MrDidact]

Yeah the dragon form relies on brute force and firepower instead of skill like his human form, the semi form has little bit of both. Aside from straight up control, its difficult for Lancelot to use his full dragon form accurately since being so big and strong makes it difficult to not only pin down on a single enemy but also avoiding unwanted destruction from both allies and civilians and their cities. I'll include both of those flaws in the cs. Anything else?

Edit: He also has no real defences against magic. Just that he's essentially immune to fire or other heat based attacks in any form, and that he has physical endurance so that he can tank alot of damage. Cold based attacks are an effective factor against him but he is just as vulnerable to most of the arcane as anyone else.