Let's try something different.
Magic Weapon Mastery Bolt Damage reduced to 50%, except when using Fusion Bolt.
Magic Weapon Mastery Bolt Damage when using Fusion Bolt is 100%.
Firebolt Range reduced to 1000 with all weapons.
Firebolt now stuns instead of knocks back.
Firebolt base damage reduced to 100 at R1.
Firebolt Mana Use increased to 20 per charge. CC+4 increases base mana cost by 6.5x.
Magic Bonuses now increase damage in a multiplicative fashion.
Magic Attack Coefficient increased to .5~1.25
Magic Weapon Mastery imposes a 1 - ([Int / 300] / 10) second cooldown on all Chaincasted Magic Bolts, except Fusion Bolt.
Hebona Set Effect increased to 15% from 10%
This fixes several things about Firebolt's mechanics (the excessive safety, relatively low cost and spammability) while allowing its (and Magic as a whole) to scale similarly to other talents, while rewarding the player for investing in MATK, Reforges and other specializations for the skillset (and fixes the problematic interaction between Max Damage and Firebolt DPS, though it doesn't address Overture but Overture should be nerfed/gutted/deleted to begin with). It also imposes severe mana costs that require investment or extra time spent potion making to mitigate. And by lowering the range, it really encourages the use of Spellwalk...except you're going to be using a lot more mana.
Pretty much, after a lot of gear and stat investment, Firebolt is a tad stronger than now (more damage but less safe and spammable), while midgame Firebolt is pretty clunky and early game Firebolt is pretty bad. This also doesn't kill Firebolt's single target potential, just forces you to invest heavily in it statwise and gear wise.
Also Crisis is the problem with Puppeteer, Climatic is balanced. I'd delete Crisis, buff Act 7, 9 and 4. Maybe have a means of CD reduction for using other puppet skills? This would make the skillset more interactive and less "spam crisis to nuke". It also kills Blaze as a dominant strategy, and we know how toxic Blaze is (terrible concept, terrible design, terrible balance, either op or useless, why does this skill exist, it doesn't even feel magey, oh my god i fucking hate blaze oh my god kill it kill it). Hailstorm probably doesn't need Crisis anymore with the QOL buffs, at most a slight reduction in full charge time, or make it scale iwth Int like the base load time.