First of all I must say that service quality at PH Hamburg has steadily improved (for me at least) since last summer and I see an attention to detail there these days that I thought was gone for good.
Guest rooms are still in need of refreshing touches though.

Regarding your stay in June: it might be a good idea to specifically ask for one of the few balcony rooms on the 5th floor well in advance. These rooms are a great choice in the summer and if you get an upgrade, they can still give you a larger deluxe room. With the AX rate I wouldn't pay up for a confirmed club level upgrade. The club rooms are not extraordinary and the lounge isn't that spectacular either. Breakfast is much, much better in the Apples restaurant than in the lounge anyway.
Dining has never been a revelation at PH Hamburg but is not bad either - the tasting menu offers can be nice sometimes. Maybe Apples will improve after the current renovation. Afternoon tea in the adjacent Park Lounge is actually quite good and way better than the afternoon cake in the club lounge.

There are tons of nearby sights & eateries. Just one example: walk down the busy Moenckebergstrasse or along the Binnenalster towards the town hall, eat a bite at a place on the Jungfernstieg and then head past the Steigenberger Hotel and St.Michael's cathedral towards the Landungsbrücken to board a Barkassentour of the harbour and the Speicherstadt before paying the infamous Reeperbahn a visit.