That would be alright. Maybe if they expand to Zelda we'll get something more extravagant then.
There is a chance of that happening right now, actually. This, alongside 12 other sets, is currently in the 3rd review wave of 2019:
...but there's still a small chance that it's actually going to become an actual set. Maybe with the new Nintendo partnership it could work but I personally doubt it.
I'm worried we might get an even worse ratio than usual with licensed themes if there's a lot of new molds. They cost thousands upon thousands of dollars to produce.
That is true.
However I think that things may not be too bad as the Lego Minions sets, which have completely new moulds for the Minions on top of being a lucrative license, are actually very well-priced.
This set with 3 minions of various sizes is $49.99 for nearly 900 pieces for example. Also the Simpsons had a blind-bag run that didn't cost any extra compared to the regular blind-bags despite every single character having an entirely unique head mould.
There's also the chance that they'd do what they did with the recent Toy Story sets and forgo unique moulds (Toy Story 3 sets had them) to just make the characters in the regular Lego style, with the thing teased right now being a kind of gimmicky outlier.