First thing I should point out is that you guys have the 1.7.10 pack, and it's not that much smaller than the 1.12.2 pack.
Mainly what I wish to know is what's the threshold for the size of modpacks? Is it mod count? Is it RAM? Is it storage? Does the version also complicate things as far as performance? You don't particularly specify these in your post about modpack requests from what I've seen.
It'd be nice to have a concrete answer because, in my personal opinion, I feel like the 1.7.10 pack and the 1.12.2 pack should both be approved together, but it would also be nice to know that having 198 mods is fine, but 238 mods is pushing it.
Just thought I'd ask incase I'm either getting something wrong, or if there's a better answer than "Too Heavy".