Hatchet and Heavy Hatchet function similarly to the Troika line, as does the Thwack Hammer. The only one unique item that could do with more expansion is the two star Wrench Wand. Axes are essentially Troikas. The Rocket Hammer functions very similarly to the Troika line, only with a different style.

Lances/Spears are, as you put it, slower but more powerful variants. It could probably work, I mean if the Calibur line can have a heavy weapon variant, it makes sense. It's a bit unnecessary, but I wouldn't mind to see that.

If we make axes a new weapon line, why not make it exactly like the gremlin thwackers'? It would work similarly to Warmaster Rocket Hammer where it is a normal swipe, then a dash, and a final swipe- the difference is that the dash and final swipe would be slightly faster, but the dash will deal no damage and go further. The charge would also work like a thwacker's and either throw an axe across the map or do a high knockback spinning attack.

A lance could be completely different from current melee weapons and have no attack chain, instead having one slow, long range piercing attack that deals a large amount of damage in a cone in front of the knight. The charge would work like a slag charge, so you sprint across the map with the lance extended, dealing massive damage to everything in your path and displacing each enemy. Or, instead of displacing them, it would be cool if you could pin every mob in front of you until you hit a wall or stop, adding some interesting and new utility as well as making it harder to use without deleting yourself or any other knight.

Just my two cents.

Having reskins of weapons is alright, however it isn't a new weapon at that point. It'd be better if such an item was a promotional item if it's just a reskin, and from what you're describing, you want a new weapon that everyone can acquire.

But, again, what's the point of axes when we can make more original weapons? I don't dislike the idea of axes, but when the suggestion is "poison troika that looks like an axe", that could just as easily be a poison troika that doesn't look like an axe, especially since swords often (not always) indicate what kind of attack style they are by their shape.

The rocket hammer is an elemental sudaruska. The elemental damage makes sense since it is a gremlin weapon (and gremlins deal elemental damage). However, the biggest draw of the weapon is the fact that, since it's got a rocket attached to it, it can propel your knight forwards on the second hit. This separates the hammer from the sudaruska, as well as makes it an interesting weapon.

So, I guess, what would proposed axes have over current heavy swords? Would they have a wider swing? Would they have a lower damage 4-hit combo where the player swings the axe back and forth in front of them at wide angles? What can we do to make them a new interesting weapon rather than "just another suda reskin that no-one will use"?

I do like your idea for spears/lances. I've always been of the mindset that a heavy piercing sword would have a stab forwards on the first swing followed by a fierce upwards thrust, having high knockdown. The idea of throwing your sword like a javelin sounds pretty great! I love that idea - perhaps it would be more of an energy/ghost sword that pierces multiple targets and deals high damage, like a no-knockback callahan bullet.

A few ideas for axes-

A one hit heavy sword

The one hit would be the spin attack from leviathan blade but with free movement and more spins, or possibly a sped up suda smash. Then their charge could be either the thrown axe like the gremlin thwackers do, or they could be a bigger normal hit, like proto sword's used to be. Kind of a role reversal from most swords.

Warmaster rocket hammer variants

Title says it all, but the point still stands. WRH is a VERY unique and cool weapon, and I'd always be down to see more of it in different flavors. They could also replace the charge for added fun, and possibly remove the third hit for balance and to make it different. Another facet to this is that it could easily have different speed values.. which would add up to a very different feel for the weapon.

A ranged hitter

Move the sword range out and extend it... but make it so that it's slow, and that your knight can't hit up close with it. This could be for like a great axe of sorts. Lots of range, lots of knockback, decent damage. If it hits fast enough it could be made to function kindly with the brandishes. Good mid range, bad close range, bad far range. Kind of like mixmaster in sword form.