My worry is that the availability will vanish due to increased cardholders and thus increased access to XN (and recently IN). So maybe there isn't a re-ticket aspect to this.

I use DL for domestic redemptions a lot and with the takeoff 15% I didn't notice too much base rate inflation compared to where it was before, but DL has been on a path the past few years to peg 1 mile = 1 cent (for ancillaries, etc. - setting a floor for the redemption value) and equating cash to mileage tickets (both in terms of fare rules, also accrual of MQDs, million miler counter includes award, etc.) which I don't know if UA is interested in.