The ~10 unique rewards you’re capable of seeing (good fucking luck, though!) from Archaeology are all neat, yes. The problem is, Fishing has ~10 unique rewards as well, plus all the normal stuff you catch is actually worth something.
To break that down:
Archaeology: 1-5% chance to get something worth a damn per combine, requiring ~7 gathers for you to actually attempt a common combine. You get 3 gathers per site, so expect to fly to two or three sites OF THE SAME RACE, which are randomly generated and might not even be the same race you want. Absolutely 0 guarantee or way to get a rare. If you don’t get a rare, you get something that vendors for 25 silver a pop and get to start over.
Fishing: You’re guaranteed to get fish no matter where you are, which can be cooked to level cooking, get achievements, and later on be used in fantastic raid-wide buffs. You can seek out pools (and now track them!) for a chance at rarer stuff, which rocks a ~1% drop rate but remains hella cool, like the Sea Turtle or Mr. Pinchy. There are quests to earn guarenteed rewards, like the Kaluak fishing derby and the chance of a +5% XP BOA ring, or just a bag of prizes otherwise.
Fish are often valuable – Alchemists and Cooks often seek them out to powerlevel, Deviate Fish let you make Savory Deviate Delight (required by every BoA PVP twink or bored level 85), and fishing up eternals/volatiles/etc are always a steady source of money.
You can fish almost anywhere – every zone I can think of has water, or at least a pool, in it (maybe not Silithus)?
Fishing is (almost) instant. No stupid hot-and-cold minigame is necessary to gather a single fish.
You don’t require a 310 mount to Fish with any sort of efficiency, unlike Archaeology. Nor do you have to fly back to the other end of the continent every 10 minutes.
In conclusion, Fishing >>>>>> Archaeology. The only benefit Archaeology has over Fishing is the insane XP reward you get from collecting a find.