Agree that the Intel O job can feel a lot like a collateral duty . . . when on the beach. Like I said, just help out your fellow JO's, capably do a few collateral duties no one else wants to do (like command security manager), and do your part to contribute to a strong JOPA/Wardroom and you're set. It's not rocket science by any means. As far as actual Intel work, its a whole different ball game when on the ship. There you'll be gainfully employed. Nothing really is overly challenging, just requires lots of time and attention to detail. Heck the majority of MISREPs I wrote really had nothing to do with Intel, but was more OPS related (which I enjoyed since it foced me to see how that side of the world operated). You also have to continue your collateral duties when on the ship, so that adds a bit to the pain. A lot of the workload will depend on what the Strike Group is doing and what your job is (SIAC, SUPPLOT, brief/debrief, etc.). Things can be really boring or really exiting. As a whole, the entire first sea tour really is heavily geared towards giving a young, inexperienced officer an understanding of how the fleet works and how all the pieces interact. You'll contribute some, but hopefully learn lots to help you down the road as you move into higher profile jobs.
I don't think the Intel community is too selective with regards to degree field - in that respect they are not that different from a lot of fields (As I understand it you can even go NUKE with an English or Music type degree so long as you have the calc/physics prereq's met). Like most everyone else they are looking for the proverbial "well rounded individual." With a biology degree and no prior flight experience I was also pro-rec'ed for NFO (my second choice). If you want to track into attache/embassy type duty as an Intel O there are opportunities for post-grad school to learn all about politics and international relations on the Navy's dime.