Sooooooo, I see most ppl spend playing they grind some skill or make money to buy training or get favor with trainers. If player picks 2-4 combat skills and decides he's done, he wont have much to do after capping those skills. Devs wont be able to produce enough explorable content to keep ppl busy without multiple skills grind. And leveling other skills for the heck of it is not everyone's thing, collectors are tiny fraction of population. Crafting keeps ppl busy if economy is healthy but without need to make huge money for trainers there is not much reasons to actively participate in market.
If I think i dont need more combat skills i lose big part of to-do list in this game. Quests and stuff can be done with 2-4 combat skills I already have. No new skills - no need to make much money via crafting, less and less things to do. Therefor a legit reason to have MANY combat skills would really help with player's retention and economic incentives.
Current reasons to get new combats skills are mostly negative ones - can be bored with old skills or can do one big thing that absolutely requires certain skill (farming money with fire AOE at panthers spawn).
Would be really nice to have some positive motivation to collect many combat skills. Yes, I'm talking about mixing multiple skill lines at same time. Ofc there must be limitation to prevent few overpowered combinations from becoming meta. Game already has attack categories like basic, core, epic etc. So why dont just allow to supplement main skills with few abilities of lower class from another skill lines, maybe with increased cooldowns? Add 4 slots at each hotkey bar that can be filled only with certain amount of Survival, Core, and Nice abilities. No more than 2 abilities from 1 skill line, no more than 1 Nice ability from skill line, no more than 2 Nice abilities from non-main skill lines at same time. No Epic ones ofc. Cooldowns for non-main skill lines are +30%.
As a result we'll have incentives to level up to 6 extra skill lines to cherry pick some abilities from them and huge playground for skill builders. More skill leveling - more reasons to stay in game, more reasons to participate in economics.
Yes, balancing will be hard but you know what? No way current skills will be perfectly balanced anyway and who cares about small balance issues in non-pvp game? As long as there wont be obvious face-roll combos of doom, most ppl wont give a damn. Not all players use skills seen as overpowered now and many use underpowered ones. Without strong competition atmosphere, reasons to pick strong skills over interesting ones can be ignored.
As you see, my idea is perfect, please make it happen. People who don't like it are evil and hate humanity (also elves and rakshasa), dont listen to them.