Okay so... if you're a reader of my site you probably know by now that I am a writer and would-be game designer who has issues with changes that Overwatch has made. Now, I pay too much attention to my site statistics (read that as "effectively zero readership") to even joke about the people wanting to hear my opinions. On the flip side, I hope that anyone who does read this understands that it is an honest reaction, not one predicated on getting money or even attention for what I say.
Basically, my reaction is "No."
It isn't "No, I'll never play the game." It's basically a reaction to the implied "Hey, are you excited for THIS?" that's a big part of the announcement. No, I'm not. I will play it and I may love it. But they haven't earned that from me yet. There are some very dangerous things they are, or seem to be, adding to the game. Even if "Level up your hero" is only for the co-op game modes, it is a violently dangerous component to add to a game design that was, fundamentally, about knowing the capabilities of all of your heroes by heart, everyone being consistently on a level playing field, and using the mechanics of a character to cement and ground their personality.
When responding last year to Blizzard's changes to Hanzo, the Japanese bowman, I said this (written, I admit, to be poignant rather than strictly accurate):
[Hanzo's old mechanics] showed such an intuitive grasp of consistency that I thought they must have people on staff who actually knew something about consistency. I figured they must listen to those people, appreciate them, pay them enough so they stick around. I feel less certain of this lately.
People have flocked to Overwatch in part because there is an overwhelmingly strong characterization considering how very little they actually do to describe the characters. It's like the difference between a cheap plastic phone and one constructed of durable materials; yes, you can use either of them, but you will have the overwhelming sense whenever you pick up the cheap phone that it is cheap. It's hard to say exactly what does it, but it lacks something, and it lacks it so consistently that even if you learn to ignore it, you never can forget it.
Not having played it--and I've been deceived by and overreacted to trailers and announcements before--the level up mechanic stinks. Like holy hell does it stink. There are numerous problems with it. First and foremost, while leveling up is commonly considered a staple of the video games industry, it doesn't have to be and is in some contexts really stupid. It is, frankly, athematic; the concept of experience is arbitrary, the concept of getting a reward out of thin air periodically has been soundly mocked for decades, and the mechanics of leveling up are usually more about increasing the numbers displayed to the players to give them a sense of progression rather than actually changing the game balance over time (it varies based on implementation, but in many cases it is fair to summarize this as "lying to the player").
To introduce a leveling up mechanic, you have to artificially and arbitrarily decide on the same number of upgrades for every character, no matter the circumstances. They have to be of approximately equal importance to every character. You can call that "a challenge to the developers" or you can call it "a decision made by marketing that nobody in the actual development of the game wants to 1)create in the first place, or 2)constantly have to maintain and balance". A character level mechanic only sounds exciting. It is a bullet point, not an actual feature.
If I were to take a stab in the dark, I would say it would probably be more fun and also more consistent for there to just be powerups in the levels (again assuming that the level up mechanic is for co-op and not standard play), powerups that may be unusable for some people but apply consistently to large groups of people--for example, better bullets, improved barrier health, that sort of thing, perhaps chosen or spawned randomly. That way rather than an abstract "if I kill five more things I get to go to a menu and click a button" you say "if I can get through this horde of enemies on the other side is a better weapon".
So, yeah. In this context, a level up mechanic stinks. "Customized abilities" (whatever that means) has a number of similar concerns to it but without the strong scent of being marketing-driven rather than design-driven.
I will also say that the writing for the trailers themselves was kind of stink-o. I mean I get it, Overwatch is not a story game, wasn't, and shan't be. They don't... really have writers. But there are some very basic sins that you don't... have to commit. One of them is "on the nose writing". For example "Look up there! That's the command ship!" "Then we know what we have to do!" Okay, I get it's a gameplay trailer and they have to convey an entire situation in two lines, but it should be an excuse to show off your writing chops. I mean first of all, virtually any character could have said either of those lines; they are bereft of character. (Well, okay, not Hammond, Bastion, Roadhog... some of the stronger personalities simply couldn't deliver those lines. But most of the weaker personalities could have) Second, if you were writing, you know, from the characters' perspective, you could come up with things that make equally as much sense, like "Let's hurry and find a way aboard that command ship" or "We have to hurry to the shuttle if we're going to get aboard that command ship" or "We need to get closer if we're going to stop that command ship"
Writing! Character consistency! Someone, anyone! Argh. Similarly in the "Zero Hour" cinematic, Tracer being cheeky about the null sector invasion makes her sound like a psychopath. "Haha look a civilian building just blew up I have to finish my line though and hope I'm not making a joke about the moment in which a dozen civilians were crushed to death by a shattered and broken building. Haha! I made it sound like I'm talking about the weather!" You want her to be a cheerful upbeat character in a somber moment and you really ought to have noticed that it made her sound like a stone cold butcher who leaves a trail of innocent people in her wake what the hell were you thinking.
Am I excited by the trailer? No. I was excited to know that there was going to be such a thing as a sequel, like, a week ago. The trailers? They give me zero good feelings. The trailers give me zero added faith in the developer. They give me nothing. Even when it feels like they ought to. Because some of the things shown off in Zero Hour would be cool if they were practical. Linking barriers? Neat. Combining ultimate abilities? I mean people have been effectively doing that from the start, just not quite so literally.
But honestly... as a person who pretends at game design, I had hopes. Hopes that they could make gameplay feel more meaningful by, I dunno, making two different games affect each other, so that if you held the point in one match, your allies had an advantage in the other, and vice versa. Hopes that they could make rounds more interesting by adding, say, MOBA-style mobs to a versus round round that you had to deal with in addition to the enemy team. Or more mundane hopes like writing that felt like a professional did it instead of a novice writer. I mean, I read a lot of novice writers--check my list of webcomics on the top bar. I forgive those people a lot because 1) they don't charge for their work, it's a labor of love, and 2)they aren't a part of a, what, five-hundred-thousand-dollar project? Million? I have no idea how much money Blizzard put into OW2, but I expected more.