HP are important; that's why I said "tax." Touch attack bonuses are rather less so; 90% of the time they're just going for 10+Dex. I'd absolutely tank my BAB on most caster builds.
To be honest, I'd suggest dropping BAB, base saves, and hit die altogether--let players invest points directly in those abilities, up to some level-based cap, like M&M does. That should give you finer control in a simpler way. If you want to have class features be a point-buy thing, you might as well cut out formal chassis as well.