You'll find some people suggesting that any show needs time to find its feet, and that simply isn't true. Many shows have nailed it in the first season, and the original series of Frasier is a prime example, starting brilliantly, then getting even better through the second season and beyond.
I'm not saying that the new show is not capable of developing into a good show, however, six episodes in, it certainly feels like it is lagging behind by a considerable measure. The cast has potential, but the character relationships still feel quite contrived, and the show is being let down by unfortunately weak writing.
In particular, what the new series isn't getting right so far, is the farce the old cast and writers could so readily run with, which was so strong in the original series. The silly part of good farce, relies on an assumption that the audience is smart enough to get counterpoint, irony, etc. If it isn't written for an understanding audience, then it can end up coming across as dumb.
Additionally, the show is relying far too much on a sense of nostalgia to carry it, potentially limiting the audience, instead of giving the new, and especially younger cast members, the meat of genuinely incisive wit through the writing. Part of what made Frasier great previously, was sharp, intelligent humour, that began by assuming the audience was also sharp and intelligent. As much as I really wanted to love this show, the writing simply isn't achieving that, which in turn is letting down a majority of the cast and may be preventing their chemistry from developing efficiently.
A real pity, too, because many of the new cast seem much sharper than the material they're being given. If the show booted some of the reliance on nostalgia, allowed much more contemporary, (dare I say new), intelligent, incisive, witty writing for the younger cast to sink their teeth into, maybe along with trusting them to play more with each other, the sharp counterpoint the writers appear to be failing to grasp, may present itself more forwardly.