Following on from a side-topic discussion with @Outer1, I updated my WDW ticket price spreadsheet now that the resellers have started to increase their prices. As he pointed out, the savings are often not large enough to bother with dealing with a reseller - pay just a little bit more, and you get your tickets linked automatically to your MDE account with no worries about slow/lost shipments.
I then took my analysis one step further, and compared the third-party prices to what you would pay WDW if you used Disney Gift Cards purchased fromTarget at a 5% discount to pay for your tickets. Lo and behold, the WDW prices were less than the discounters in many cases.
Using UT as an example, the majority of tickets are cheaper from WDW (with Target discount) with the following exceptions: 3-Day+1 PH was 9.39 cheaper and 3-Day+1 PH+WPF&M was $18.70 cheaper through UT. There were some other ticket classes that were cheaper at UT (5-day PH, 3-Day+1 and 5-Day WPF&M, and 5-Day and greater PH+WPF&M), but the savings was less than $4 for all of these tickets.
OTC tickets have more substantial savings, particularly in the premium ticket classes, but I suspect that is because they are still selling off old inventory and their prices will come into line soon. Note that with either reseller, Base MYW tickets were always cheaper through WDW (with Target discount).
Looks like WDW is putting the squeeze on resellers, as I remember the discounts being much better in the past.