From a personal ideal perspective, I've only ever wanted cash shops to hold items of an aesthetic nature. I'd perhaps feel comfortable with Torch durabilty items which gave a tempory boost in stats for an hour or so but that's it, and certainly no xp pots as explained. I feel that should be saved for special events like Christmas etc.
So yeah as said before, I'd rather pay a £5 subscription or something a month to support you guys and the running of the server. I'm not saying everybody would be behind the idea, however I at least feel as though you and the team should have asked the community first before launching your server. Maybe you did already? I dunno.