we need official rulings on a lot of these assertions, since if they're true then alchemy basically sucks and the rules for it are stupid.
1) when, exactly, did the arrowhead become part of the arrow? i'm pretty sure most pre-modern arrowheads were affixed to the shaft separately, unless twining something together gives it all one "aura." by that definition, anything contacting the preparation becomes part of its aura, meaning if you drop that death touch preparation you just zotted everyone standing on earth. oops. similarly, if i have a prepared blade in a wood handle, i fail to see how the piece of alloy steel and the barely-polished natural wood somehow combine into a single object that is the preparation when they're radically different from a magical point of view in terms of their individual object resistance. if the blade is prepped separately, it's a separate thing, isn't it?
2) Gloves aren't sufficient to keep you from contacting a preparation? seriously? then the things are nothing but landmines (except when they then zap the entire earth when they touch it) if part 1 is true, then... you couldn't ever carry them on your person; by point 1, it's touching the thing you're carrying it in and you're touching it, so zot. even if point 1 isn't true, then i have to carry the goddamn thing in tongs? everywhere? what's the minimum safe length of tongs i need so that it doesn't contact my aura?
3) you can't set off a preparation in the same phase you throw it? if that's true, honestly, fuck 5th edition. that would take one of the best ideas in the game and turn it into the dumbest thing ever. that's like saying you can't cast a touch spell until the pass after you've made the touch attack. might as well call them nice hug spells. hey, what if i throw the preparation at the ground and set it off, does that make it not an attack action? what if it's a mana barrier prep, not a death touch? is that suddenly ok? oh crap, that barrier manifesting might make that astral creature disrupt? does that make it an attack and not permitted? dumb dumb dumb if true.
4) define "ruins the lynchpin." if it's a thick liquid, as long as most of it stays in one place does that make it okay? you could make a really thick contact preparation and put it in a splash grenade or super squirt capsule then, assuming it stayed in one piece more or less on contact. this, incidentally makes play-doh the preferred medium for touch preparations. does drilling a hole in an arrowhead so you can screw in a modern shaft "destroy the lynchpin?" if you tell me that drilling a hole beforehand into a rock makes it worked enough to qualify for object resistance, i fucking give up; this game is too stupid to live.
suffice to say, i really look forward to these being officially clarified by actual writers of the rules in official errata or faqs at some point.