I made a proposal upthread, and Ranger Wickett approved of it, though wasn't sure it'd be OP elsewhere.I have been trying to solve a very similar puzzle over the last weeks: A Dex-based Kobold Queen Bee Berserker.
The Kasurigama solves one of the problems, but not the other. It is a dual-wielding two-handed weapon, which would qualify for Feel My Sting and Furious Critical without the need for Heavy to be tagged on, but is not finesse (so no attacking with Dex, still a possibility for small STR based d12 attacks).
Another piece of the puzzle could be the O5E feat Revenant Blade from Eberron: Rising from the Last War, which requires you to be an elf (maybe cultures count?) and gives the Double-Bladed Scimitar the finesse property when you wield it (which makes it a finesse two-handed weapon).
A trio of magical solutions in the lightsaber theme would be the Sun Blade, which is a longsword (in O5E, in A5E the wording is more vague) with the finesse trait, the O5E Dawnbringer (longsword with finesse) or the O5E Sunsword (longsword with finesse). Finally: Windvane, an O5E legendary spear with the versatile and finesse traits.
Any update from the writers regarding a Zeitgeist errata?
And he's the guy who wrote Zeitgeist in the first place sooo... I think you're good to use that ruling?