QuadVees are an example of a "new" technology which, in game terms, is being evolved "on-screen" - as in, during the time in which Catalyst Game Labs has taken the lead on moving the timeline forward from the Dark Age Era into the IlClan Era.
While there was a throwaway mention of a "QuadVee" somewhere in a MW:DA/AoD product, the first actual rules, Record Sheets, and Unit Cards for these designs emerged in CGL publications. Indeed, the earliest prototypes were "tracked" QuadVees; only later (both in-universe and in game publication terms) did the Notos, the first "wheeled" QuadVee, emerge.
Going forward, I hope that more can be shown in terms of how much farther the QuadVee concept can evolve in terms of unit design; in how well Clan Hell's Horses succeed (or not) in terms of incorporating them into their combined arms doctrine; and, perhaps, in whether or not any of the other known Clans (to include the Scorpion Empire) might one day take a closer look at QuadVee technology for their own uses.
Although, since even the Horses deploy QuadVees two to a Point, it would seem best to compare them to tanks and other combat vehicles, rather than "standard" BattleMechs, in terms of where that place in the Horse touman might end up being.
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Actually, the Horses - as well as their estranged sibkin over in Clan Stone Lion - are noted as investigating other technologies also.
The Machina Domini system was originally designed and intended for use by the Word of Blake Shadow Divisions. However, the Horses have been slowly chopping away at producing a Clan variant, which made use of ProtoMech Enhanced Imaging rather than the Manei Domini's VDNI. No word yet on if or when they might field such a unit, however - or, for that matter, if they coin a term with fewer Blakist connotations for it by then.
Meanwhile, the Nova CEWS system deployed by Society Septs during the Wars of Reaving has been taken on board by the Stone Lions - but (at last reporting) only for testing on ground vehicles, and only for use against non-Clan opponents. Which, post-Reaving, would include the Horses themselves...
Indeed, now that Clan Sea Fox has gained access to Ares superheavy tripod technology as isorla from the Battle of Terra, I could readily imagine the Horses at least considering taking a look at how such units might (or might not) work in the Horse touman.
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Speaking of Clan Sea Fox: they (and, by extension, anyone they are open to selling their wares to) have designed units which make use of certain new technologies on board. Consider the hardened armour used on the Hammerhead, to give one example.
But what they and others have yet to do is to develop a "generational shift" in BattleTechnology, which weaves a broad range of advances into a new "standard" by which past eras' advancements can be measured. Or at least, no-one is known to have created such a thing just yet.
Might this happen at some point between 3152 and 3250?
We'll have to wait and find out...