Well, due to being Vow of Poverty, the slotlessness only really matters for class features that care for item slots like Meldshaping or the Crown spells. For those situations, though, it does pretty much crack open the intended balance point, since you get to very freely go to town on whatever you please.
And, as previously mentioned, I'm pretty sure the very major bases missed with regards to mobility and recovery are specifically because they can be handled by party members and class features. The Paladin doesn't really need healing if you give them those ability score bonuses, because their features turn Charisma and/or Wisdom into healing fairly directly, since they have Lay on Hands and get the Cure line, alongside the Charisma to saves reducing what they take. The Monk only needs permission to go vertical, any straight speed bonus makes them start zipping around quite stupidly, and the AC bonus on VoP being measured for wearing a chain shirt already makes their AC bloat a wee bit. As in "can make Pit Fiends miss 3/4ths of the time", before throwing in any allied caster buffs.And some of the things that are missing is stuff that can be provided by party members.
Or by class features.
But i think its silly to call VoP directly cripling just because it does not cover all bases, for all classes.
And if you are the caster, like a Monk 1/Paladin 2/Druid 17, well in that particular case you just grab Serenity and enjoy having astronomical AC and saves, alongside almost on pace item number bonuses that carry into your delayed-by-three-levels Wild Shape and ignore any dispel attempts.