On May 16th, the plan terms, coverage, and pricing will change. Your commitment will not.
If you use the plan to order a free upgrade, then you will be subject to a new 2 year agreement.
The big benefit here is this:
Most promotional deals for equipment upgrades are based on account tenure, service history, and local competition. They do not last for long, and may not include the type of equipment you want out of an upgrade. (Targeted sales)
The D* Protection Plan will now allow you to get a free upgrade every two years, regardless of these other factors.
The intent is to keep your equipment as up-to-date as possible so that you continue to enjoy the new things being developed. I speculate that from a warranty perspective, this may also make sense in that replacing your aging equipment with new upgrades could prevent frequent issues as older equipment starts to fail eventually.
Why send a tech to your home several times to fix an old unit, when for the same cost (or cheaper) you could be given a new unit that will be less prone to issues?
All opinions expressed are my own and do not reflect the views of DIRECTV, National Electronics Warranty, or any other entity that I share affiliation with.