I would also like to see more done with fishing. My idea would be to make it a profession that you level, something like:

1)Different qualities of fish. Green, blue, and purple of each species.
*White quality still gives meat. Green, blue, and purple give different quality levels of fish oil, no meat, as the fish is not usable after attempting to extract oil.
*Fish oil is an optional ingredient that can be used in any provisioning recipe. Similar to alchemy, oil from different fish have different qualities, except that their is only quality for a type of fish. For example, lets says salmon fish oil adds a health bonus. Green salmon oil adds 2.5% health bonus to a recipe. Blue salmon oil adds 5% health bonus to a recipe, Purple salmon oil adds 10% health bonus to a recipe. If the recipe does not have a max health bonus then the oil is used and nothing happens( inert). This way what type of fish you catch and extract oil from matters.

2) Legendary Fish - This fish is so rare, most people dont even think it exists. If you catch one, it will give 1 to 3 fillets. If you manage to find the recipe for it( can only be obtained fishing) you can create a fish dish( per fillet) that will boost max health magicka, stamina, health recovery, stam recovery, magical recovery for 4 hours.

3) Crafted/looted fishing poles. You can loot fishing poles with special abilities from fishing. You can craft better fishing poles if you find blueprints for them. Fishing poles use a combination of woods, metal, and cloth to make. Better poles increase your chances to catch more rare fish. Your standard pole will only ever catch normal( white) fish.

4) Net fishing/Commercial fishing- Not everyone can be a commercial fishermen. Net fishing requires a license. Each license upgrade allows you use different nets. License become available when you level up your fishing skill. To level up your skill you turn in whole fish( not filleted). Obviously the better the quality of fish( green blue purple) the more you gain in level. Fish also have diminishing returns if you turn in the same type of fish. So turning in 5 longfin and 5 dhufish will yield more experience than turning in 10 longfin.

5) License levels:
- White( level 5): Allows you to cast bait nets
- Green( Level 15): Allows you to cast fishing nets.
- Blue ( level 30): Allows you cast drag nets
- Purple (level 45): Allows you to cast trolling nets and charter a fishing boat( mini game)

6) Net types:
*Bait net - a small net that catches mostly bait and sometimes crabs. Also tends to catch trash item. Sometimes will catch non trash items and fish. Higher quality nets improve your chances to catch more per cast as well as better items/bait/fish.
* Fish net - A medium sized net that allows you to catch mostly fish and sometimes items. Bait and trash is more common with lower quality nets. Occasionally you may catch higher end items or more rare fish. Quality also affects chance of multiple items. It is possible to catch hostile creatures such as alligators, which will attack you when you open ( loot) the net.
* Drag net - These are heavy duty nets made for cargo recovery. They will catch fish but primarily will snag items and cargo containers. Great for treasure hunters however their size makes them unusable in most rivers and streams.
* Trolling net - This net is the only net allowed to be used on a charter boat.

7) Net fishing how too:
* Nets are cast like a ground targeted AOE.You let the net sink( a meter will move as it sinks and when its full the net hit bottom) then tap a button to pull it in. You can pull it in at any point. Though letting it hit bottom will increase your chances of catching something.
* The net must be fully in the water. If any of the AOE circle lands on dry land, the net will not catch anything and your chance of destroying the net increases by 25%.
* All but the trolling net can be cast from land/docks/etc. The trolling net can only be used on a charter boat.
* Nets may drop amphibians such as crabs and alligators at your feat. Be prepared to defend yourself( does not apply to trolling nets)
* Nets are similar to lockpicks. Each use you have a chance of it breaking. Higher quality nets have a lower chance of breaking per use.
* Nets are crafted using plant fibers of special( new) plants. Like nirnroot, the nodes are specific to that plant. Green, blue, and purple nets require additional ingredients , such as cloths, leathers, and metals in addition to the rope fibers to reinforce the net.

8)Charter boat types
* Lake boats are the cheapest but you can only bring 2 nets.
*Coastal boats allow 5 nets but coast more.
* Deep sea boats are only available to a level 50 fisherman. They are the most expensive but allow 10 nets and give you temporary storage for your loot/fish on the boat( Accessible for up to 4 hours)

9)How charter boats work. Visit a charter captain and pay a small fee to charter his boat. If you do not have trolling nets in your inventory, he will tell you to return when you have some( you must have at least 1) This starts the mini game.
* A map will come up of the area the captain will take you. It will be divided in sectors. Each sector will have a fee. Areas that the captain knows to be good for fishing or treasure due to rumors or reports may have an increased fee. Areas that are more dangerous such as around jagged rocks( where shipwrecks may of happened or rare fish are seeking cover) will cost more.
* Select a sector and you will "travel" there. You will then be standing at the stern of the ship where you can control the movements of the net behind the boat. You may see things in the water like fish jump, debris, snags etc. These are signs of both dangers and possible catches/treasures. Use your movement keys to guide the from side to side bringing it in or letting it out.
* You have 30 seconds before the captain makes you reel in the net with your catch. However, their is a chance every second that your net could break and you lose everything. But their is also a chance you could end up with a big catch. You may reel in the net any time after the timer starts to end the trolling and prevent further risk to the net breaking with whatever you have caught so far. So its all above maneuvering, timing and luck.
* Once your net is in, it is trash( it can be deconstructed later for usable parts) and you are done with that sector. You may travel to another sector if you have another dock and pay the fee for that sector.
* When you reach the dock the mini game is over. You may go out again but the price increases for the charter and sector cost by 25% on each additional trip(IE: Trip 2 is 125%, trip 3 is 150%, trip 4 is 175%, etc). This is a global increase and resets daily, so you cant hit every charter once on the cheap.
* NOTE: At level 46 you unlock a skill that decreases your charter/sector cost by 10% per level( 5 levels total)

10) Group recipes: Need something to do with all that extra fish? Have a fish fry. Fish fries are group provisioning buffs.
* Green Recipe - Max Health only
* Blue Recipe - Max stam and magicka only
* Purple Recipe - Max health, stam, and magicka.
* 12 fish require per recipe, feeds 12, must be in group. Placed on ground for other to "loot" to receive buff.
* Once placed others have 15 minutes before it disappears. Last for 1 hour( regardless of recipe color)
* Stacks with all other buffs, 50% as effective as purple provisioning buff. IE: If max health from a purple gives you 5k hp then group gives you an additional 2.5k hp.