I haven’t been on club trips for a while, would love to join if timings match.
Zermatt has an ok priced campsite English - campingzermatts Webseite!
Basecamp would make sense more in Täsch, camping is more comfortable, cheaper and great starting point for Alphubel and Allalihorn SW ridge. Preise - Camping Täsch
We climbed this past summer Zinalrothorn in 1st week of July, very dry glacier, but it was an exceptionally dry and hot year! Maybe last two weeks of June could be a safe bet for classic mountaineering.
Sion valley has nice crags e.g. above Brig and also some big walls, but it’s probably not worth going there for a rock trip, as nearby Furka Pass, Grimselpass or Simplonpass make more sense as a summer destination?
Dolomites is always a good idea, but it’s worth making a backup plan too, as it’s often very rainy. To be avoided from last week of July onwards if you don’t like crowds. Campsites expensive, wild camping tolerated very little, but the climbing is absolutely amazing, some of the best 
Corsica is fab, a top destination with stunning beaches and all the rock pools… The best climbing seasons are October or April. I was in Restonica and Bavella this September and it was very hot, absolutely not possible to climb in the sun. Most of the climbing is south facing, so we started running out of shaded things to climb in our 2 weeks there. The topo is great, very informative 
Its possible to stay in Col de Bavella and walk to some of the climbs, but I would say that you need a car if you want to really get the best of the place, the big walls are on the east side with no wild camping or accommodation available, just pigs inhabiting old abandoned buildings.
Val di Mello is beautiful, Luna Cadente and Kundalina are world class. A word of warning: the high mountain granite is hard for the grade and quite macho, absolutely minimal bolting, often A2 passages, so you have to read the topo carefully. Also, the walk-ins to any of the walls beyond Qualido are absolute killers. But, there’s donkeys, mini ponies, Italian mountain huts with fabulous food, lots of bivvy-hotel-boulders and infinite amount of (scary) granite climbing that will yield a lifetime of stories. If this didn’t convince you enogh, the valley is lush and full of great bouldering.
Chamonix sure is always a safe bet, expensive and crowded but I think if you time the visit to the sweet spot when Envers hut hasn’t opened yet, it can actually be done cheap 
I will be in and out of Chx, so I’ll be up for a few routes for sure! Aosta valley is on my way home to Finale Ligure, so will try and make a stop there if anyone is around.
And if anyone ever visits Finale, you must let me know!! We live 15min walk from the campsite, so drop me a message to catch up for a beer or a climb.
