I think some levels of appetite changes are normal. It's hard for me to gauge your kitty's situation without more information. If you notice it, then it is probably a legitimate tapering off of his appetite.

I would try a wet food or different variety of Orijen before baby food. Baby food is good TEMPTING stuff, but more of a last resort. I'd be more apt to use it for giving medication (in small amounts) or getting cats to eat that have stopped entirely, rather than what you are describing. It is definitely not nutritionally complete for cats (as you probably realize).

One thing that many cats LOVE is canned sardines. Use the ones canned in WATER only (not oil, etc.). You can feed it bones and all because they are well-cooked and the bones are soft enough to mush with a spoon. It might be worth mixing one sardine in with his dry food daily. They are a great source of omega-3s!! This was recommended by a veterinarian that I worked with and trust entirely. She suggested this for all canine and feline patients as it is a more "whole food" way to supply omega-3s (vs. supplementation) and generally much better accepted than pills.

Another thing to consider is what I like to call food toppers. They are great because they can be added to dry food and don't go bad when left out like canned food or sardines. They are great for those cats that nibble nibble nibble throughout the day. My two favorites are Kitty Kaviar and Rosie's Rosedust. The first is dried bonito (a type of fish) flakes. Most cats go crazy for them, there are many brands available, and they are a good source of taurine. In addition, there are tuna flakes on the market that are also well liked. The second is a 100% beef product that you can sprinkle on food. My cat was a big fan and enjoyed the variety from fish treats.

Hope that helps! Let me know if you have questions.