If the new series has nothing but endless "fun stories" I think I would grow tired of it after several episodes. The same with "likable characters," there were characters (example 7 of 9) who were great for and on the show, but who I wouldn't want to be around in real life. Some of the heroes can be unlikable.Sometimes yes, but the future Federation/Starfleet should never be pollyanna. The insistance from some fans that the show depict a utopian future is obsurd.
Though, GR was among those who insisted upon a utopian future, specifically for TNG. Often referred to as the "Roddenberry Box."
Also, I'm not saying that characters can't be unlikable, or do unlikable things. But, personally, I would not go for a show where the lead is generally unlikable as, just with likability, that is a one note trick and gets boring and/or annoying and I would turn it off. Extremes is not the place for characters, at least not in the long term. One merely need to look at G'Kar from Babylon 5 to see such an example.
Well, for me personal there are actually some things more important than being purely entertaining: Humanism has always been at the core of Star Trek, and I want the characters action still be defined by their humanistic ideals. And I want a somewhat scientific approach. Those are for me personally what seperates Star Trek from other ation/adventure-based sci-fi properties. I can get pure dull entertainment anywhere else, comicbook-movies for example. But it's a personal distinction i make, probably not one general audiences would care much for.
First of all, as much I know that humanism is a part of Trek's framework, I also appreciated the fact that TOS and DS9 took some time to explore some downsides to that philosophy. So, as much as they are guided by their ideals, I would also like to see those ideals some times lead them to a bad choice or two that they have to go back and correct.
As for scientific, that is an interesting question, mostly because I wonder how much the new series will be beholden to past Trek in terms of tech. And this is a genuine question on my part, not a demand, as I think the writers can take some of the technological understanding from contemporary science and apply it to understand Trek tech and explore it in different ways.
But, they might also hold on to tech staples too. So I'm curious to see that explored.