I would like to see modern cam action tangs on their slip-joints, something that allows light opening and strong resistance to closing without needing a stronger spring. Spyderco, Boker, and Enzo all manage it with arguably less high tech folders. The rest of the Lion Steel slip joints are great, but the basic traditional square tang is a let down.
Textured G10 inserts on the Thrill would be good too, that is the slipperiest knife I have met, so easy for it to get away from you.
I'd like to see more stag / animal horn scales. I recently grabbed a CK02 in stag from collectorknives and ITS FRICKIN BEAUTIFUL (my new favorite knife)
Id love to see more of their patterns in stag or horn scales
I'd like to see modern full tang or hidden tang tanto, with either traditional or american tanto tip, Sleipner steel and guard either being part of the full tang like on M5 or the part of the handle like on M7. Brass guard if you're feeling ambitious...
I didn't really see other Europeans makers make tanto knives, except Extrema Ratio, but those are just not really tantos and look deeply ugly.
I think that with LionSteel designs and quality combined with flawless fit and finish and attention to details - you'd have 0 competition.
Tanto by LionSteel would most likely swoop the market.
Almost every company has at least one bowie in their offering, and majority of knives at the market are drop point or clip point making it harder to choose for the customer.
But I also understand if you just dislike the idea of tanto knife or tantos just aren't your thing.
But if you had M5 or M7 in Sleipner with same handles, slightly upsweep blade and tanto tip - I'd no doubt pick that over regular M5 and get the M7 too.