I am USNA class of 1991. I was a SWO at graduation (lo these many years ago) but am pretty familiar with Navy Intel.
There are few service assignment slots for Intel, because the Navy Intelligence field is quite small. If you think about it, this makes sense, because a small cadre of intelligence personnel will provide information that supports a squadron, an air wing, or a fleet staff. Many ships do not have an intel designated officer onboard, but instead have a enlisted personnel on independent duty and/or a Surface Warfare Officer that has shipboard intel as a collateral duty. I've heard it said that there are fewer officers in Naval Intel than people in a Carrier Air Wing.
There is an increasing interest in intelligence that relates to Cyber Warfare, but there is still a strong need to have people with a clear understanding of analysis, clear writing skills, regional expertise and language abilities. As a point of reference, the officers selected for Intel through OCS typically have graduate degrees, language ability (often in difficult, in demand, or multiple language), and frequently personal experience in regions of interest.
I'm not sure I would agree with the difficulty of managing a shift work watch schedule. I know that the SWO requirements for shipboard duty sections have changed a lot over the years, with the result that there are relatively fewer duty days. (I remember being in three duty sections, ie serving a duty day every three days, and in some circumstances being port and starboard, alternating duty days, particularly as Duty Engineer or Command Duty Officer, when there were few qualified onboard. I don't think these extremes are common anymore.) On the other hand, I remember many days on sea duty when I showed up onboard around 6 am and didn't leave until after 7 pm. This was especially common in shipyard periods, where we had a full work day supervising work on the ship and then had to do sets of engineering or damage control drills after the day shift of yard workers knocked off. An 8 hour schedule with a definite turn over time and specific days off would have been incredible.
On the other hand, I remember some periods when my dh was on shiftwork with watches and was trying to sleep during the day. I would take our (then) young kids out of the house, just to try to keep things quite, then come home around dinner time to see him before he headed out for the night watch. Like many aspects of the Navy, our various schedules both seemed normal and accepted and a tremendous burden. I think this had more to do with who I was working with and for than the particulars of the hours expected.
I think that there are relatively more opportunities for going Intel now than when I was a mid. I agree that joining the Navy if your only goal is Intel is not a good plan. There are many things that change, including the needs and policies of the Navy. I don't see a problem with going USNA or NROTC if your first choice is Intel as long as you will also be content if you end up with something else. (SWO used to be the fall back, but last year I understand they turned down requests to go SWO.) I would offer similar warnings to a student who declared that his/her only desired career would be Navy Pilot or SEAL.