the other unusual builds aren't fairly reliable, in a sense you're restricted by a few handful of skills that are on a long cooldown.
HV and AP has, on the other hand, have plenty more skills that scales well and has a low cooldown.
and AP by itself can be boosted with attr, so even if the skills are on cooldown, you can wack them all to death.
and in terms of raw bulk, going into entertainer skill tree (duke, cat, etc.) gives you sumo suit, the most ridiculously overpowered shield i've ever seen.
sumo suit scales with HV up to a certain point, with means you can go full HV for dukes and get the remaining HV from comps, then switch to HP or DP.
on the other hand, prima still has more benefit with pure AP, just get the HV from comps.
sumo suit has 50% damage reduction at 301HV, that is the cap as well.
skills that scales with DP is effectively just siren song, for full house DP decreases it's backlash damage.
skills that scales with HP are siren song, impaling rage, power charging(gambler), heavy hit(gambler,meta), and mass destruction.