Visited the GPLH and yes indeed the resort is very impressive which makes sense for sure with the price they are asking. Most definitely a 5 star with all the bells and whistles and impressive selection of top shelve liquor which Hubby and I indulged in (yes we are naughty sneaking into resorts like that....love it). Given the size of the resort yes I could see you believing that the Seven mile beach is not that impressive, but honestly it would do my head in staying at the GPLH. Way too many people and many so very pretentious.
Just as well there are different strokes for different folks.
If I was to splurge then I would recommend the Riu Tropical Palace, it was fancy enough but a more a warm, down to earth feeling to it.