LACs by definition focus on the liberal arts, therefore few LACs offer engineering or business programs (although exceptions do exist). Computer Science arguably is not a “liberal art”. Some LACs still include only a relatively small number of CS courses among the Math department offerings.
I have not found more than a few LACs with Linguistics departments that cover the full gamut of core subjects in that field (phonetics, morphology, syntax, semantics, historical/comparative linguistics). Swarthmore is one of the few. Carleton seems to cover those subjects, barely. Most of the others will be weak in this major (if they offer it at all.)
Anthropology and Sociology are 2 other fields that many LACs don’t seem to cover too strongly. Some of the above colleges (including Amherst, Williams, and Swarthmore) do not have separate anthro and sociology departments. Beloit and Bryn Mawr are 2 LACs with good reputations for anthropology.
Regional area studies programs will be limited at virtually all LACs. Oberlin and Wesleyan have had strong Asian Studies programs in the past. Middlebury is very strong in several commonly taught modern languages. However, don’t expect any LAC to offer the variety or depth of area studies programs you’d find at Berkeley, UChicago, Michigan, Harvard, etc.
There has been some discussion about the limits of Mathematics programs at even the most selective LACs. It has been suggested in at least one CC discussion that very few LACs offer solid preparation for graduate work in pure Math. A few LACs (Williams, Carleton, St. Olaf) do generate about as many alumni Math PhDs (even in absolute numbers) as Brown, NYU, Penn, or Northwestern. The Math offerings at some of the other schools on the above list may be fairly limited, or may attract only a very small number of majors (which you can look up in each school’s Common Data Set file, section J).
There is a consortium of small college programs in Geology called the Keck Consortium. Amherst, Carleton, Wesleyan and Williams are members. I wouldn’t expect other LACs on the above lists to be as strong in this field.
At any rate, the goal of a liberal arts college isn’t to cover a wide variety of specialized arts & science subfields. They leave that to graduate schools. What you can expect at a selective LAC is more or less rigorous exposure to the economic, mathematical, historiographical, etc., way of thinking in approaching enduring and difficult problems that come up in each field. That exposure typically will include a lot of discussion, writing assignments, readings of primary source materials, possibly field work or original research projects, all under relatively close faculty guidance. The number of courses listed in the catalog doesn’t necessarily tell the whole story (although of course it’s not irrelevant if you want to major in a department with very few courses or faculty members.) If you want exposure to bleeding edge research or specialized sub-fields of your major, you may be better off at a research university.