For me, it's generally the reduced park hours/staffing and entertainment cuts that are eroding value for me. The entertainment cuts over the years chip away the magic, but I imagine first time visitors don't have a comparison. The reduced hours, I feel, have had a big impact for us. It really squishes the crowds, and nullifies much of the benefit to rope drop and/or closing. And it makes it tough to make an afternoon break feasible, depending upon our plans. Our last trip in August, MK hours were 9-10 all week, with one EMH until midnight (I think one am EMH too).
So, my strategy when I go to WDW, or anywhere else, is to do a lot of research so I know my options in order to roll with things and be more flexible. I have found in my last few trips to WDW that when unexpected things occur, such as ride closures, weather, crankiness among the ranks, it just seems much tougher to pivot, and certainly the shorter park hours and even entertainment cuts contribute to that, in my opinion.
I do believe that Disney is not considering the long-term effects on the brand. Now, this is completely anecdotal and really just my observations over time, but Disney has much more competition now for vacation dollars, and around me, they are not winning the battle. I live in a fairly affluent small town - but definitely a range of middle class - in New England, so an easy flight to WDW but most people do fly (I just say that because most people here will consider the cost of flying to go to Disney, like they would many other vacation destinations).
But just like people rave about vacation home rentals to decrease costs of visiting WDW, vacation rentals have also opened up affordability to lots of other destinations. After school/summer vacations, I'll hear about some trips to Disney, but more to the Caribbean, Mexico, Central America, Europe, National Parks, etc. And again, these are generally middle class families, not super wealthy. And when I do hear about Disney trips, the parents often talk about it as if it was something they had to endure, not enjoy! Like, the kids enjoyed it, but thank goodness we never have to do that again! Or they just wait the kids out until they outgrow asking to go! I would think Disney would not want to cultivate that kind of reputation over the long term.
The first time my husband and I took our kids was 2009 - neither of us had been since we were kids. The kids had a blast, and importantly, we as parents had a blast, so we kept going. Our family has had many trips in the last ten years, and has built nostalgia with WDW, and memories over time, and our kids are fully WDW "indoctrinated", so to speak. We still enjoy that we have old favorites on trips and always find something new, and as WDW trips have become more complicated, my "skill set" has increased to keep up, since we do still enjoy it at this point. And again, this is totally just my observations, but I don't see a lot of families like mine around me and that seems rather short-sighted.