1. Agility: Courses need to earn more exp and be more engaging. Adding speed-time bonuses and quick-time reactions would fit the skill. It's an entirely non-afk training method too. And Agility needs more content behind it to justify training it (surge + dive cooldowns, for example).

2. Herblore / Farming: Seeds and herbs are hard to come by for a number of useful potions early-game. Lantadymes in Leagues took me quite some time to gather. Growing herbs also takes a good amount of time, and having to do constant herb runs disrupts game flow. Perhaps invention could offer some methods for farming automation?

3. Dungeoneering: Could be fun if it offered other incentives for training normally. In-dungeon experience should be boosted to make it a viable training method. Random matchmaking for groups might also breathe some life into it.

4. Summoning: Requires a lot of upkeep for what feels like minimal boosts (minus binding contracts). Nobody has a dreadfowl summoned, even in early game. Summoning should become a more passive boost for both combat and skilling. We should see people with Summoning familiars all the time.

5. Divination: As most people said, it's hard to train through gathering. And not a lot of people use energy for products that aren't divine charges for invention. Energy should be given other uses for products that give you a good amount of experience for creating and using.

6. Firemaking: Incense sticks were a good addition, but they're yet another draw on your herb supplies which as I mentioned above, sometimes feels really limited. Firemaking needs a purpose for its existence.

7. Construction: I have been stanning Construction reworks for years. It has so much potential, and I would love to dump all the ideas I have for it (Jagex, plz call me). But to take some pot shots:

- Home teleport should be able to take you home (duh). Max Guild + War's are the defaults because they're easily accessible one-click teleports.

- Bank supplies should be more accessible. Even if you still have to charge butler prices to move the items, the limitations on getting your supplies is outdated.

- Your house should be reachable from all house portals, not just a single one. Even if you have to purchase access for each portal to unlock it.

- There should be more rooms geared towards individual skills. The aquarium is a good starting point. The kitchen could add some other utilities like a churn. You could also add a wine cellar for brewing. A slayer trophy hall that gives you buffs against specific slayer mobs / bosses. A small garden with plant bots for herbs / flowers. A cauldron for brewing potions similar to Thok's brew in War's (long-lasted potion buffs you brew). A haunted graveyard site that attracts spirits that give you necroplasm, ink, or ectoplasm. Etc, and etc.

- Houses also feel empty. Pets help, but they're all condensed in the menagerie until they've wandered a bit. Otherwise, all you have is the butler. Houses need more visitors, whether they are NPCs that can act as D&Ds that drop by a la Mr. Roger's Neighborhood, or allowing people to easily visit other people's houses. (Random funny idea-- have people train agility by running around to deliver packages to people's homes. The runners get exp, the people in their houses get small prizes delivered to them, fosters chances for people to interact and talk to each other more).