A module that is a new main engine node which changes how you move and enables a tank playstyle that would let you ground boost foward quickly but gain the mobility of a tank and deal damage on collisions with enemies during boosts. Alongside a seperate option for leg armor part and frame changes/additions. The new engine node and aesthetic options can be used on all frames (Skeleton, Rex and Spider) and combinations (Helios node on Zephyr legs).
Just to clarify this is not a entire new frame idea like Rex or Spider
Module/Engine Main Node
The ground boost could look like AC surface gliding or Wanzer gliding if there are no tank tracks enabled. Other features for this module could include ground boosting into enemies causes damage based on accelleration/momentum and weight. You got the manuverabilty of tank meaning you could ground boost forward and backwards very quickly but cannot strafe as well. Just like Helios, jumping when using the ground boost you can use that momentum built up to allow for quicker mobility when switching to thruster flight by jumping and attacks dont slow you down when ground boosting.
As a main engine node, it could influence the movement stats to correspond and better balance the new playstyle with buffs or nerfs to certain stats. Mainy durability, acceleration, power and armor with stuff like fuel capacity and ammo reserves being varients that cater to a specific kind of playstyle like melee, range or balance.
Just like Helios, the new part itself could be linked to a existing part as to keep the amount of parts overall the same, no loss of decal or accessory slots rather than something like a full on leg change like AC Tank legs. No need for a redesign, just some more animations and a new part that is just attached on.
As for design/frame ideas, it could be like the Frame Arms where its a simple addition for the back of the ankle or possibly something that goes underneath the feet. I would prefer the prior as you would need to redesign the feet, both toe and heel.
Just as a reminder this is a seperate option which could be unlocked when researching the corresponding node that can also work with any Module.
This makes the most sense to how a tank frame would work.
I think the version without the transformation would be far more likely to be realised.
Though, I’d prefer if the tank tracks were integrated into the feet itself, rather than atached externally.
Some examples from Dual Gear: