Far as I know, Power Swords aren't that stupendously rare, given most chapters have somewhere around a hundred of them, and the Imperial Guard has quite a few and so does just about everyone else in the Imperium.
However, doubling or tripling or something the cost of everything, and making vehicles more capable of surviving, wouldn'tbe a bad move. Or, what I think should really happen; make artifacts more meaningful, and make master-crafting possible (at the measly price of ranging from 5 to 50 times as much as the original item depending on various things!). Not rarer, they're already stupid rare to find one that's not chaos tainted or daemon infested, but with a bit more history, maybe even starting out with some(unless Fresh Blood; relatedly, Crafters could increase the ease with which you master-craft, and there could be a Chapter Advantage called Ancient Traditions or something that increases your starting artifacts and/or the number of artifacts you find that have a hiatory directly related to your chapter). Make them a bit stronger, more visually impacting, extra bonuses from the morale boost of holding a sacred artifact of the chapter...
I would say that without a geneseed farm letting you roll in Requisition, certain wargear things become meaningful(Plasma guns, oh dear Emperor their cost...) Yeah, it's not much of an issue to accumulate enough requisition to collect a shitton of them, but you aren't going to just be buying one thing, and if you don't have any extra left over, you can't gradually work your way up to improving your chapter, giving all your 'sergeants' power swords and plasma pistols, Bikes for an entire company, Iron Halos for every Captain and Company Champion, etc., because it costs everything just to maintain the chapter and keep up with losses. And while this might be grimdark likw the setting, and thus 'realistic' for 40k, I don't think it'd be very fun to never be quite able to keep up. It's about victory at great cost, not dying slowly and terribly alone in a world that hates you. The former is exciting; the latter, depressing. And if you can't build up, what is there to tear down?
Also, please oh god please make escorts worth a damn now that it takes forever to get them back...