I get that, but that's not what we want
Forget the 25 galleries thing - let's bump it to 40 & use this site as my example:
http://www.bustyporngirls.com/
It's a 1 page site: 4 columns, 10 rows, all galleries tagged Boobs. So let's say today was our launch & everything is new. We want things to look different tomorrow, but we only have 2 new Boobs galleries. So we want those 2 to load 1st (to get them some exposure since they are new) & then the rest to be pulled from the 5,321 other galleries that we have tagged Boobs in the admin.
On Thursday, we only have 1 new Boobs gallery. But we want it to at the very least, appear that we did a big update, so that 1 goes 1st, followed by 39 random. Hey, it's new to the surfer
Friday we have no new Boobs galleries
But, wanna keep up the appearance, so we throw another 40 random galleries at them.....
The way you're explaining it, we'd have 37 of the exact same galleries showing up on Wed, Thu and Fri - and Thu & Fri would look exactly the same. Who wants to bookmark a site that basically doesn't "update".
That's the method to our madness