Agreed on slow, enjoyable losses given the, well, purpose of this game.
I'd also like to add for Slimantha specifically that for a growing player, her specific card that sets to 30% player size makes it basically pure rng on whether she bothers to use it and get an instantaneous comeback or not, making it near impossible to establish a large size difference and use the interesting big cards. I think the flood of slime shrinker cards is a much more thematic and interactive mechanic for her to come back with, and the 30% card could use a rebalance.
On the opposite side as well but less related, when getting really tiny, it's annoyingly hard to avoid the basically-guaranteed-lose vore play situation if you're not particularly into that.