I feel like a lot more positions should be added (e.g. Footjob, Handjob, Titty Fuck, Double Handjob, etc.). However, instead of relying on the devs I'd rather try and see if I can implement these myself. Would it be possible and if so how? Thanks in advance.

Possible? Yes. How? That's the hard part. You can manage a passable looking titfuck by turning off collisions, but that's not practical. Adding the new animations, like for her pushing her tits together, hasn't been revealed yet - though tweaking the existing animations may produce results.
As much as I love a good titfuck (yes, that is my fetish) it's not worth the effort currently. However, if someone is determined enough, I'm sure it can be done despite the current constraints.

Turning off collisions negates what is so innovative about xsp imo. I hate that that's even an option...

Sometimes that innovative part is just a bit too bouncy, IMHO

Well, yeah. Crude hack is crude, but effective.