That's one of the genuine downsides of PoE. In Torchlight II (not the best ARPG ever, but decent), as an ice wizard or whatever, I remember using a wide variety of different abilities strategically: an ice cage to protect myself or trap enemies, fullscreen ice storm thing, a more concentrated directed ice attack, a damaging ice teleport, and an AoE on-enemy-death life and mana drain.
That's because most/all active abilities in TL2 have a cooldown, so you're forced to use different skills simply to fill the void of the downtime.
Plus even if they didn't, the skill leveling system itself doesn't support going all in with a single skill of choice - you'll have plenty of skill points left over. Plus, some skills don't actually get that much better with further investment due to diminishing returns, again forcing you to spread out.
Most of the secondary active skills you pick this way would be temporary buffs or situational debuffs.
Meanwhile, PoE supports any level of complexity, entirely depending on a player's playstyle.
Take an RF build, for example. You can alternate between the two extremes and anything in between:
* "look ma, no hands!" tier: RF is activated once per map. Auras are precast. The only active skill you use is shield charge, it's used to proc fortify, EE and EO. A modest cwdt set up on top of that.
* Maximum engagement tier: shield charge to proc fortify and EE, orb of storms to proc EE and EO (and arcane surge for scorching ray), enduring cry to get endurance charges and extra life regen, decoy totem to distract beefy targets, self-cast scorching ray to melt bosses faster, recasting golem occasionally because it dies, vaal lightning trap for more bossing damage, possibly a self-cast curse to get that extra bit of edge. Good luck finding enough gem slots and skill bar slots for all of that.
Same build, VERY different levels of engagement.
I could do this thing for a whole variety of build types.
