Yes I agree. The resonance is limited, for example. But if I set the limit for the resonance a little bit higher it didn't sound good and explodes. You can try tweaking the limit and multiplications inside the object a bit, but I think I got pretty close to the limit.
And yes It's based on that filter from musicdsp.org. I tried a few of the others too but didn't manage to get them working. I did make most of the Moog filter from musicdsp for VCV and they worked fine, but had some issues with getting them woring with Axoloti. but this one worked 
I think implementing same filter on different platforms will give you different results. I am not 100% happy with Ladder1, but I think it has a good and different sound, compard to other types of filters for Axo.
Maybe oversampling it a couple of times would do it some good, resonance wouldn't explode at as low settings as it does now. But for oversampling on Axoloti I am a bit lost. I bet you would be able to get a better sounding and more resonant filter When you oversample for example bob~ filter in PD it does that raises the level of when the resonance blows so. So it will probably acts the same for Axoloti
That said, I don't think Axoloti is the best choice for bass sounds. It shines on so many areas but bass is in my opinion not the strong side of Axoloti.
About the muug~ for pd. As far as i remember that filter is pretty heavy, even in PD. So you might get it working for Axoloti, but I think it will be very heavy on Axoloti.
