Yes I think this has been discussed on here a bit as well but this is likely a key capability going forward both for legacy platforms and NGAD - although the later will have this capability baked in from the start. I would assume that part of the NGAD program also includes developments in long range AAM's. The article mentions specifically that 5 technologies are being developed as part of this program and each will mature at different rates and implemented once ready.The USAF could actually utilise the sensor / shooter roles in the very near future by using a F-35A / F-15EX combination. The F-35A wouldn't need to carry external stores so would remain LO, whilst the F-15EX is able to carry a significant amount of stores and a ratio of 1 F-35A : 2 or 3 F-15EX would prove to be quite devastating.
Edit to add Boeing's loyal wingman example. Might be a more economic option geared towards export markets but could provide a similar type of capability that you mentioned at lower cost. It's also interesting to note that Boeing's published illustration of it's Super Hornet submission to the Canadian fighter competition featured a 14 missile loadout, certainly insinuates that it can also be used as a missile truck.
The stealthy Airpower Teaming System drone has a snap-on nose that can accommodate a huge variety of payloads and can be swapped quickly in the field.