I'm still undecided on the Klingons - they have potential as long as they don't become a one-note culture that universally buys into Kahless, and I hope actually displays the organizational principles a spacefaring state would need. They are an Empire after all. On the one hand I was really really entertained, and their dialogue about Kahless made perfect sense in Star Trek context, but on the other hand there was seemingly absolutely no attention paid to the secular military TOS-era aspects of their culture - which worries me in its absence, since I would like the two to fit. Are they being turned into a full-on religious state? I'm a bit wary of them being turned from a 1940s military dictatorship with rational objectives into something more like a combination of part Tolkien Ranger of Ithilien lighting the beacon of Amon Din to call the heroes of the world, and part jihadist terrorist lighting the beacon of xenophobia to call the faithful to holy war. It could work, since Kahless is their Aragorn "just-king" figure, but it could also end up being as bad as the living stereotype they became in DS9.
In David Mack's "In the Name of Honor", it's implied that beneath the dishonorable imperialism and fanaticism of TOS era Klingons, there was a fundamentally good message in Kahless's teachings, it's just been lost, and the morally decent Klingons reclaim this legacy around The Undiscovered Country, eventually leading to peace with the Federation.
The reason I'm cautious about this?
It raises questions about how much respect Star Trek should pay to warrior cultures, which on the surface seem honorable, often proclaiming ideals of universal justice, but in reality have rarely been so. Hollywood, being a couple of centuries removed from Knights and Castles, sometimes have a romanticized view of their moral goodness or justice, because of literature from the 19th century that glorified them - but the reality of actually living in such a culture was probably not fellowships vanquishing evil every day - but rather people being forced into conformity through fear; hiding abuse, slavery, lacking choice, suffering utter lack of accountability - the Anglo-Saxons enslaved 10% of their own population in the time when Beowulf was written - the Central Asian kingdoms were full of slaves captured from neighboring infidel cultures, sold into harems. Were they not living up to their ideals? Perhaps. Or perhaps the ideals needed examination. This was what I think was behind Ezri's famous line to Worf in DS9 about how perhaps the Klingon Empire wasn't worth saving. I don't know the answer.
I'm hoping Discovery will be nuanced, and explore all this and more. Actually their portrayal has been nuanced so far, and we haven't seen enough to judge - the show could go anywhere - and it's exciting.
In terms of visuals, I think a D7 style Klingon battlecruiser or two among that big fleet, or a bit of a beard/goatee/hair on one or two of the Klingons, would have served to make the transition less jarring for fans.
What struck me about the makeup when we first saw it in images, was that the makeup seems to be a full head mask, it looks like it fits over their head. In the past however, Star Trek deliberatly only used to apply makeup in sections to the areas of the face that didn't effect the actor's ability to emote - famous example being the Cardassians, who look very alien, but the makeup does not obscure the actor at all (think it may have won awards). The Into Darkness makeup was really good in this respect actually, and I think it would have been ideal for updated Klingons.
I don't know if audiences will find the Discovery Klingons more alien looking and modern. I would have thought their behavior was more important than how they looked, but maybe skeptical people looking at promo images will see them as cool and more alien looking than other shows. I would hate for them to just re-design, say, the Cardassians, along similar lines, making them look far more lizard like or something, when they are fine as they are. But lets wait to see how Kol's actor looks in the makeup, and if they introduce other varieties of Klingon.
(Just don't mind the cholesterol 
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