I don't get the gnashing of teeth and rending of clothes over "nostalgia". So what if they bring back past character and actors? How and why is important to me. Is there a story there?
I'm neither gnashing nor rending, but am apprehensive.
My primary concern is that it will be at the expense of the current cast and characters. I really like Jurati and Rios, and want to see much more of them. To a lesser extent, I'd like more of Seven - while she was over-exposed in Voyager, here there's the chance for some better material. (Don't particularly care about Raffi, and I was pleased that Elnor died, at least temporarily). In contrast, I just don't care about any of the other TNG characters or actors. They've had their time, and most of them weren't particularly interesting back then.
Plus, the hints as to at least one new character for S3 do not bode well for the story.