I've dug around and did some research, it appears this system was released in 2016 and was quite obviously never finished.
I started playing over a year ago (I only played briefly for a few weeks before quitting) and I remember the team system being in it's exact current state ever since.

This system was a great idea and should have never been overlooked and neglected for so long.

Team System Suggestions:

All non-combat skills need to be added to this system and each skill needs at least one perk and potentially multiple perks unlocked at varying levels.

These are just some suggestions of perks I think would create the incentive to utilize the system and promote team growth. -

Cooking - 20%  to cook two fish at once.
Woodcut - Currently offers a chance to receive noted logs.
Fletching - 20% Chance to fletch or string two bows at once.
Fishing - Currently offers a chance to receive noted fish.
Firemaking - 20% Chance to burn two logs at once.
Crafting - Craft two molten glass for each bucket of sand & seaweed used on a furnace.
Smithing - 20% Chance to smith or super-heat two bars at once.
Mining - Currently offers a chance to receive noted ores.
Herblaw - 20% Chance to not use a secondary ingredient while mixing potions.
Agility - Sleeping Bags will instantly reduce fatigue at the same rate as Beds/Hammocks.
Thieving - 20% Chance to receive double loot from a single pickpocket.
Slayer - 20% Chance to receive double loot from an assigned slayer monster.

These are just quick ideas of perks I threw together, I don't believe any of these to be game breaking or over-the-top considering right now perks aren't even unlocked until a team reaches level 80 in a skill. This could definitely be looked into further and perhaps others have better ideas or have suggestions for varying level unlocks instead of just at 80 Team Skill.

Team Experience Drops - Just as it's important to see personal experience drops I think it would be a great idea for any team experience you personally gain to be shown for each action.

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Overall this system was a great idea that seems to have just been forgotten. I know for a fact that making it a priority to complete this system will give players motivation to stick around and develop their teams and chase team & personal highscore ranks.

I know a majority of the players are PvP focused, but there is a lot of us that do prefer to skill and play casually. That said, with the Holiday events coming to an end here in a few days, it's going to be crucial that we work on finding ways to keep the player population we've gained and increase appeal to all aspects of the game and not just the PvP scene.

I appreciate any further suggestions and ideas that anyone else may have towards improving the system.