lotta people tend to fall jaina into one-trick builds, and given the tendency to faceroll the keyboard for kills, its not hard to see why, but the where jaina can order her spells does shift with some of her talent interactions and can provide situational variation is less organized teams.
The big perk of Q is that it works with a lot of talents:
reach helps keep further back (or pierces further in)
lingering chill enables Ice lance Q procs without other spells (ie, getting closer or losing blizzard threat)
Fingers of Frost adds more damage and mana control
getting Q cdr from ice lance allows jaina to sustain ice barrier (helpful for dueling) or spam more casts with icy veins.
The key part of variation for jaina is finding where youāll be able to trigger chill procs to then combo off the other abilities as some talents needs targets to already be chilled for them to work.
ie: taking numbing blast (root) at 16 doesnāt do any good if the player is trying to lead-off with W, but if they only poke with q, they also wont be able to chill multiple targets to root more than one hero.
On the other hand, Frost armor applies chilled to enemies that have attacked jaina (basic attacks) so she can forgo some of her combo structure by taking a poke from a ranged hero, and then going into comboes after that.
Q-focus is usually easier to learn, while W and E talents are very situational.
Since cone talents tend to need targets to be chilled as is, they really only work off of Frost armor for defensive tactics to kite close range heroes (ie, like a samuro trying to gank jaina: multiple targets for cone cdr attacking from multiple sides) unless youāre leading off with a close-range blizzard.
E talents are more of a pve jaina, but still need a hero for poke for the cdr, so imo, those only stand out in the mage brawl were multiple jainas can be on one team to all benefit from chill, and then have the range/aoe and boosted damage to just outsiege the side with fewer jaina.
That said, Iād say jaina does have sequential ālearnerā talents to try to adapt to player her.
at 1, lingerning chillās extra duration allows Q poke to self trigger, so its easier to stay back and not commit to chain-chill-comboes yet, then as you get some more practice with range and build a preference for combo order (using which spell to initial chill to trigger the other spells and talents) you can experiment with other talents.
Icy veins is nice for the blow-up, but shield is handy for either dueling maps, or if there are pve targets to sustain building up the shields off one target (like a boss or immortal). The shield surge can be nice, but since jainaās normal cdrās allow the shield to fall off, its not uncommon for the shield to end up not blocking enough damage to offset the cdr an mana control icy veins provides.