I agree with you fully! It's just if the developers are super dead set on including SP, which I personally think they shouldn't, that they should allow Warlocks to infinitely cast spells with limits.
If they were able to, I, along with many others, would like to see many of the warlock's SLA put into play....but i'm not sure if spiderwalk is in game, and the dismembered hand could be hard to convert to ddo.
So I understand that they want to make a class like the warlock have spells instead of the SLA that are to hard to code into game, but if they could instead make the SP regen -OR- have the spells have cooldowns of 5 ~ 10 secs per lv of spell, then have enhancements that lowered spell cooldowns by 1/2/3 secs. Basically, make the limited spells they get BECOME the SLAs.