The thing is, I never got to do a true "general surgery" month during my clerkship-- never saw a hernia repair, ostomy, etc-- so doing a general surgery one seems daunting. I did a month of CT and a month of breast and enjoyed and performed best on the CT month, since I enjoyed it more. I didn't want to "start from scratch" for an AI.
If you are applying to general surgery 5 year residencies and have some intention of being a general surgeon, I would consider it imperative that you rotate on a general surgery service. You definitely don't have to have seen everything, but it's a good idea to have seen some hernias, or gallbladders, or bowel stuff, or trauma, or some of the day-to-day grind you'd be dealing with in residency. Breast is nice and part of what general surgeons can do, but rotating on a breast-only specialty is a world apart from a general surgery residency or not breast-only practice. Similarly, if you do a 5 year GS residency you'll rotate on CT (but probably not practice it that much as an attending unless you do a fellowship) but sub-specialty rotation on CT is a different kind of world apart from a GS residency/practice.
My recommendations:
1. Figure out if you want to do CT-only and maybe GS only as 'backup'. You'd better be a very strong candidate for CT only.
2. Rotate on a general surgery service regardless.
-If you're doing CT-only and don't have time for all the AIs you'll be limited in perception of your GS application if you don't have it; if you absolutely can't do one, at least spend serious time shadowing on a GS service. Cozy up to your home department in case you don't match.
-If you're interested in GS but don't have a true 'just general surgery' rotation at your school, I'd recommend acute care surgery (if you have it), colorectal, surg-onc, or MIS for the belly operations; SICU or trauma for the hours and complicated patient population.
