You don't like either the Defiant, or Voyager? I take it you're a bit older than me then, and possibly grew up in the 60's?
But honestly dude, you've nothing to worry about in my opinion regarding the Reliant. I'm 1864% sure she's the next Federation ship they're making. As for the Grissom (it's been a bit of a running joke here since they announced the Romulan Bird of Prey like I said), I honestly don't think it stands a good chance of being made, I'm afraid. I do love the ship/design, but I can't see them choosing that over the main ships from the other two series. Then again, this is DST, who like you say, are doing stuff completely randomly, so you never know! I'd buy it and love it, but really don't think it should be given precedence over the hero ships of both Deep Space Nine, and Voyager. Being fair as well, TOS/TMP-UC fans have been spoilt rotten by DST. So many versions of the original Enterprise, refit, A, and now Excelsior, as well as the Phasers, Tricorders and figures. After the Reliant, I think us TNG/DS9/Voyager fans deserve a little bit of love to be honest, wouldn't you agree?
You'd be incorrect in the assumption of my age. I'm also aware of the 'running gag"; I'm not joking when I say I want a Grissom. I stand by my previous statements of it's merits. And no, I do not agree with your assertions. Both Voyager and Defiant can be found in other forms including both toys and models, but the Grissom is not as well represented. I'd like to see it made. Were DST to produce a replica of either Voyager or Defiant, I would not be purchasing them; that may put me in the minority but that has never factored into my decision making up to this point, nor will it in the foreseeable future.