Marvel had themselves a meeting with some of the retailers to try and figure out why their sales are tanking so hard. There were some mentions of the pricing of certain books at $6 or even $10, and Marvel's trade collections being pricier than other publishers, or people being sick of constant events. The one that has gotten the most notice was the comment about customers not liking diversity. Books starring women, or nonwhite characters.
Once it got noticed and started catching some heat, Mr. Gabriel, the VP of sales who made the comment quickly stressed that wasn't Marvel's position, oh no. It was what they were told by the retailers. Either way it seems to be pointing the blame for the poor sales at the customers. If only they would buy more of our comics, our comics would be selling better! Well no shit. I want to point out that if the comics were cheaper, perhaps the customers would be more inclined to try things they otherwise give a pass to. That would certainly be the case with me (and I'd probably be more forgiving of a book I spent $2 an issue on, rather than $4). But that doesn't seem to be the case anecdotally. Cheaper books carry a connotation of being unimportant, and a segment of the customer base has been trained to only care about "important" books*.
I've found the newer characters hit-or-miss, personally, though Marvel really does need to be focusing on courting potential readers besides me. They've already got some of my money. A lot of the nebies I'm indifferent to, a few I dislike, a few I really like. Just like with the new characters that came out in the '90s, or the '80s, and so on.
G. Willow Wilson made a point that if you want people to be invested in this new legacy character you're selling, maybe don't crap all over the character whose legacy they're inheriting. Make it seem like it's a codename/title worth assuming. Wilson made it clear Kamala Khan really looked up to Carol Danvers, that she felt Danvers was a great hero, and that taking on the name "Ms. Marvel" was a big deal for Kamala. That she felt a responsibility to live up to that name.
But in a lot of cases, the preexisting character kind of gets dragged through the mud. Making Sam Wilson Captain America isn't a bad idea, but then making Steve Rogers a HYDRA agent out for world domination is. Taking on the mantle of Captain America should be a big deal, but deciding the guy who originally made it a big deal has secretly always been a bad guy kind of undercuts that. Sam's not trying to take a name that carries weight and build upon, go in directions Steve Rogers wouldn't have considered, he's trying to rehab it. Wasn't that a big part of what Kyle Rayner had to struggle against, that he inherited the title of Green Lantern after the writers made Hal Jordan a murdering lunatic? That certainly didn't help Kyle's acceptance from fans of Hal.
I sometimes strongly dislike Kate Bishop because I feel Clint Barton is being written like an increasingly incompetent putz to make Kate look better. In reality, I think the writers just think Clint should be written as a moron, separate of whatever they're trying to accomplish with Kate Bishop, but it's not always easy to keep that in mind. And if I think the character I like is getting the shaft (no pun intended), I might not be real happy with the character I think is benefiting from that.
Marvel spent the last couple of years trying hard to push the Inhumans as a big deal. There wasn't any demand for this, but in theory, it wasn't a horrible thing to try. You can never tell when you'll find that magic combination of a writer/artist team with a strong vision the fans will love. The problem was it also felt like Marvel was shoving the X-Men into the background. The X-Books still had 5 titles (a heck of a lot better than the Fantastic Four), but there was the sense they were being sidelined in favor of characters Marvel had movie rights to, and the fans were just expected to go along with it. And the fans didn't. If the Inhumans' titles had been better, maybe it would have worked, but as it stands, fans weren't buying it. The Inhumans couldn't become a tentpole franchise like the X-Men were, simply on the strength of Marvel wanting it to happen.
You could probably put Bruce Banner's recent death in Civil War II under this heading. Amadeus Cho's book had already established Banner wasn't going to transform again, and that was that, but Marvel went ahead and killed him anyway. Which I'm sure was more about feeling the need for the shocking death mid-event, but if you're a fan of Banner, maybe you see it as him being taken off the board entirely so Marvel can give the name Hulk to other characters and push them. To give you no other option if you want a Hulk fix.
I know there's a segment of the customer base that is gonna want things just a certain way, like they were in (time period that individual has strong positive feelings about). I'm that guy sometimes. And That Guy may never buy in to the legacy character. Maybe because they feel strongly about the earlier character. Or they just won't buy a book with a lead character who is part of an underrepresented demographic. Or maybe the new character just doesn't connect with them. Marvel should keep trying Also maybe find more people who aren't straight white dudes to write some of those comics. But at a minimum, try not to dump all over the last guy who held the title in the rush to make the new one the Greatest Thing Ever.
* I have still never figured out if it's that Marvel (and DC) trained us to only care about important books, by trying to tell us we needed to buy every comic with "Disassembled" or "Infinite Crisis tie-in" stamped on the cover, or if we trained them to slant their publishing lines that way with what we bought.