I went through a remarkable period from the mid-2010s to the early 2020s of nailing a large number of powder days over there. I recall Tony describing it as "James's enviable luck in the Alps."
Liz and I enjoyed the last half of that run of powder filled trips, 4 of them in the 2017 through 2019 seasons, plus the 2014 Zermatt trip that changed Liz' mind about the Alps. 2023 was probably similar to many western trips with powder only on the 3 Via Lattea days out of a 17 day trip. But I'll contend those Via Lattea days were way more enjoyable than a typical powder frenzy at a western US resort.
Nonetheless, if you don't think a ski trip is a success unless you get a lot of powder, you're going to be unhappy on something like 3/4 of one week advance planned ski trips. Cat/heli or January in Japan are the only places you can do any better with advance booking. It becomes more obvious with EMSC's posts that given his lack of flexibility, those are the options for destination skiing that he would enjoy most.
Other criteria:
1) Is there enough off piste skiing with pleasant surfaces, even if not powder? This is the minimum that ChrisC or EMSC would want. From reading ChrisC's reports, you can see that there is lift accessible terrain far beyond what we have in North America that has to be appealing to skiers of EMSC's caliber. ChrisC is sometimes over there like EMSC now with an advanced booked group, but hangs around for another week on his own to chase some of that big mountain skiing.
We'll have to wait for more detail from EMSC, but Trois Vallees has enough high quality off piste to have an enjoyable week even if not powder. I've had quite a few Iron Blosam weeks like that as most of you know. Our week in Trois Vallees started out worse than EMSC's I suspect. The base was thinner and it had not snowed for 3 weeks when we arrived. My ESF guide managed to show us some interesting off piste on the first two 9AM-1PM sessions, and after the second one I ripped 16K vertical in 2 hours of butter smooth groomer corn in Orelle. So despite my fanatic efforts to improve the odds of a good advance planned trip, once I'm there I try to make some lemonade out of the lemons.
Val d'Isere a year ago was also without new snow and a majority of off piste had been wind hammered or melt/frozen. However, since I had been there before I poked around and found some quality off piste routes, something one of our two guides had failed to do. I'll be interested to see how that goes with EMSC at the end of the week. Val d'Isere's off piste terrain quality is exceptional IMHO, and if even a modest fraction of it has decent snow I'd be surprised if EMSC is disappointed.
2) So the next question is how unhappy will you be if mostly confined to groomers? After that run of lucky trips 2017-2019 we have had quite a few of those days. We enjoy those still given the scale, scenery and especially if it's a new place we have not been before. The scale of so many of those new places has been such that we often skip lunch because there is so much to see, then indulge our foodie cravings at dinner. On longer trips we don't mind at all if a majority of the days are like this. I think it's clear EMSC does not find this acceptable.
3) The worst case scenario in the Alps is the bad weather/bad vis days, especially if there is little terrain below tree line (Val Thorens being a good example) or if it's raining at low elevation. With this kind of forecast, we take off in the car and do something other than ski. That was Liz' first rip in 2001, and if you are on a typical one week package deal you are kind of stuck.
I had only skied in the Alps twice before retirement. Neither of those trips had powder but I did get to ski high quality off piste terrain at Grands Montets, Verbier and La Grave. But for EMSC's standards I would not advocate returning to the Alps for skiing until he can implement a flexible schedule like ChrisC and I do. For his guys' trips with mixed abilities and a limited number of days, it's not a great idea.