My thoughts on my first GB GC were that the game has a lot of potential, but is still missing some major stuff.
I am a TW veteran though, so I am not left at admiring the basic division of strategy and tactics etc. which are all familiar elements from earlier games, and which make the game series one of my favorites.

My problems:
- some bugs, but they will get patched. I am not encountering CTD's too often, so I will not argue about this.
- AI is sluggish in attacking you at normal and even in hard mode. NO NAVAL INVASIONS IS BAD. GB is immune to invasions if you keep out of the mainland territories. This takes any strategical considerations too easy.
- AI economical skills are not good, they will get "locked" with situations where they don't have enough troops to win (evaluating attack potential) and that leave their economy stagnant, so they will never do anything useful (france looks like this often).
- Tactical combat goes to melee mode really really fast. Ranges are a bit short. This was fixed in one mod I play, and I am loving the musket combat now. Even enemies prioritize musket combat more in the mod. Vanilla game is not *special* enough to feel like a different tactic is needed to deal with muskets, compared to RTW or MTW.
- AI artillery is super good compared to player artillery. This is not a good way to fix difficulty.

Overall, I still liked my first game a lot, but it left me aching for some real challenge.