Having Skill Trees will help story-only players, non-gamer partners and journalists to play by having the default Skill Tree build be really easy and hard to get wrong, while others can be more sophisticated with greater control of party utility, buffs, debuffs or a bit higher damage potential.
Not sure what your vision of this is here. Like, would this cut down the number of actions in some way, or offer simplified versions? Otherwise, this sounds additive, and therefore only a way to, well, add further complexity, which wouldn't help anyone who's already struggling...
On that note, though, one thing I kind of wish the game had would just be like... easy hotbar setups/layouts to try out based on a given button arrangement. Something algorithmic such that if I like using 1, 2, 3, 4, R, F, C, V, B, T, G, Y; Alt-1, -2, -3, -4, -Q, -E, -R, -T; Shift-1, -2, -3, -4, -R, -F, -T, -G, -Y; Ctrl-Z, -X, -C, -V, -B... the game might suggest sets of skills to be arranged into those sets of keys (by contiguity).
To start with a simple example, let's say I'm a
fresh player with the default keybinds of 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, -, =.
I'm a Gladiator, so I start with Playguide on 9, Teleport on 0, Return on -, and Sprint on =. Fast Blade goes on 1, and as I level, Fight or Flight goes on 2, Riot Blade on 3, Total Eclipse on 4, Rampart on 5, Shield Bash on 6, Iron Will on 7, Low Blow on 8, and Lob on... Ctrl-1. To say the least, that's... kind of awful. All the more so when I end up with Provoke on Ctrl-2, Interject on Ctrl-3, Rage of Halone on Ctrl-4, etc., for a default combo of 1-3-c4.
What if, instead, upon acquiring Riot Blade, the game would make better and job-specific use of Active Help (as you suggested) to show that Riot Blade and Fast Blade are linked, and so one might want to place them together, across 1-2 or 2-3 or 1-s1? When acquiring Iron Will, it'd note that the action rarely ever needs to be used and might therefore suggest placing it further towards the edge, leaving room for other actions. And when acquiring Rage of Halone, again, it would note that it, Fast Blade, and Riot Blade are connected, suggesting a position for that.
Heck, let players sort choose among different recommended keybind layouts and import a recommended job hotbar layout for it, with mouseover on the not-yet-acquired skills making providing a simplified usage-centric explanation of the skill and making very obvious when you'll acquire it.