I have been a Diamond for 8 years and aside from 2 specific properties that have "lots of suites" that routinely upgraded Diamonds to suites (the former PH SF and PH LA), I've only received "complimentary" suite upgrades (not booked or confirmed in advance anyway) 6x - one time each at HR CVG my mattress run property, HR SDF (it was a very slow Thanksgiving night), HR ATL (not sure how busy they were at the time), PH Vendome Paris (they were sold out for 2 nights), and 2x at the Highlands Inn (weekday - they are known for trying to upgrade Diamonds to Suites).

These are out of probably 250 stays - so it really is the exception rather than to be expected - as specified by Hyatt's T&Cs which does not call for complimentary upgrade to suites just to best non-suite room for Diamonds. Any further upgrade is going above and beyond.

Also, the "quality" of the suites do vary greatly from property to property - from what you described, you were upgraded to the base entry level suites (which is what is called upon when booking a suite using points or confirming with the Confirmed Diamond Suite Upgrade).