There are definite trade-offs. The danger of going during a non-peak season is that there might be rides down for refurbs, getting ready for the busy Spring Break season, and there may not be as many entertainment offerings.
Right now, the only things that look like they will be down are Grizzly River Rapids until March 9th and Matterhorn, but that will be closed until June. Fantasmic! is listed as being closed until later in February, but says it may not reopen until "later in Spring".