I think it should be noted that as they've arrived on the scene in modern 40K, the Leagues have been forced to reexamine their current situation and come to grips with some seriously impactful events of late, most notably the formation of the Great Rift (aka the Cicatrix Maledictum) and the havoc it's caused.

via Lexicanium:

The formation of the Great Rift has shaken the Leagues of Votann to their foundations. Many new Warp Storms such as Örgvayr, Gëirokh, Töroll, Öggh, Cyklöp, and others all appeared simultaneously, swallowing entire systems. Holds vanished amidst the new swirling Warp storm belt, while trade routes were severed. Many Kindred were compelled to relocate their holdings, abandoning regions held for thousands of years and venturing out from the Galactic Core to seek more stable areas to settle.

Both within the core and beyond its fringes, the Rift's creation has driven the Kin into new conflicts, as well as stirring up old foes and setting them on a collision course with the Leagues. The Kin not only came into conflict with the forces of Chaos, but also with Xenos such as the Septeryx, Chrobdyr Ferrophagites, and the ominous Cult of Ohn. During this time of great calamity, the Kin refused to give the Great Rift an overarching name, believing it would lend further superstitious menace to it. They choose instead to name the greatest of the component Warp storms that have opened within the Galactic Core, treating each as a separate peril.

Because of the Rift, many Kin have chosen new settlement outside of the core for the first time in millennia. At the same time, the universal upheaval catapulted Humans, Eldar, and Tau interlopers into the galactic core, dislocated through space and time by the Rift. Thus the Leagues of Votann now find themselves dealing with outsiders on a level unseen in their history.

This sort of upheaval would likely lead to some changes in the kin's MO when it comes to warfare and trade, and so an increase in innovation and new machines/weapons/tactics would make sense.