I know what you are saying about "broad strokes" but ask yourself this? If the show was to do a crossover with any old show would it really feel like the same universe with new people playing KIrk,Spock and McCoy and the Enterprise looks modern and updated?
To be honest, I don't think DSC is going to cross over with any of the old shows. TNG is older today than TOS was when TNG started. DS9 and VOY are both relics of the Clinton administration. A child born the day ENT went off the air is in puberty today and will be old enough to drive a car in four years. The only
Star Trek production DSC could plausibly cross over with would be Kelvin Trek, and of course they're set in a different timeline (although I suppose there is the possibility Chris Pine, Zachary Quinto, and co. might be persuaded to make an appearance as their characters' Prime Timeline counterparts).
Basically, like it or not,
Star Trek is now so old that DSC is going to be
de facto more or less on its own, I suspect, in a way that no
Star Trek spinoff since TNG Season Five has been.
I some point these changes are so big that it's hard to see these changes as all happening in the same universe. It's one thing to change the Trill
Is it? Because if the Trill go from being bumpy forehaders to being spotted and Trill symbionts go from taking over their hosts' bodies to forming a new gestalt personality with their hosts, that means that
millions of years of Trill evolution have to be pretended by the audience to have gone completely different. That's a pretty damn big retcon there -- at
least as big as finding out that in the 2250s, they really
did have holographic interfaces and heads-up displays and touch-screens instead of paper print-outs and analogue clocks and jelly-bean switches.
Unless your going to a time period that is undefined. "Discovery" I think would have fit better with it's look being 20 to 25 years till "TOS" as oposed to just 10.
You don't even know the story DSC will tell; it's ridiculous to make that assertion yet. You're just reacting to production design aesthetics, not to the actual story.
Continuity should be respected, but not blindly worshiped. Diverging from continuity, even in service to plot, sometimes especially in service to plot, can look like a cheat. "Wait a minute, the engines couldn't do that last week."
I think that's totally fair. Internal continuity within DSC should be respected -- Burnham shouldn't be African American one week and then Ethiopian next week, for instance. But I also think there needs to be some wiggle room if discontinuity makes for a better story.
Canon is only a word used in internet arguments. It can be a handy guide post but it should never be the rule. True creativity thrives only when unfettered, and if it's a choice between a good story or the chains of canon, a good story should win all the time.
Former Doctor Who producer Terrance Dicks, and one of the franchise's more respected writers said it best: "Continuity is only whatever I can remember." I sometimes feel more could learn from this attitude.

And
Doctor Who has a pretty good attitude towards continuity, I think. It matters when they want it helps the story they're telling, and they don't worry about it if it doesn't.
Well, there kind of is a Robin, in The Dark Knight Rises.
Doesn't count!

What's ridiculous is that it even needs to be defended. It's called doing things right.
"Doing things right" depends upon what your creative goals are. That is subjective, not objective.