I'm not so sure about that. The last pack was an animal pack, but the update brought a lot of building pieces with all the furniture and items from the shops, with the wallpaper pieces too. I think this would be a good moment for changing again the pattern and get an animal pack for Spring, especially if they add again building pieces to the update. Everything is possible and we shouldn't take anything for granted.
I've also been thinking that maybe, if Frontier wants to continue making DLCs but now they are busy with the consolie edition, we might get an "easy-to-make pack" now with many "clones" and save the complex animals for a future DLC when they have less things to port to console. For example, a pack with North America river otter, American black bear, wapiti, Caribbean flamingo and hellbender (plese before killing me remember that this is not a final DLC, but an easy to make one until they are done with the console launch). Those animals wouldn't require new animations or a lot of work, but are still famous animals common in zoos which would be nice to have (especially since console players won't get mods).