As of the May 2011 update, best nuking legs for BLM. The HQ augment is MAB, and it goes upto +4 (+9 total).
Other augments include Elemental skill, Blood Pact delay, Pet Attack and Pet Crit Hit Rate
First of all, there is no loss of MACC when you use Morrigan's slops. 10INT=5MACC. Also, these might beat Morrigan's by a few dmg on AM2, but Morrigan's will win on tier4.
As a taru backline Redmage these pants are pure win as a macro piece for Magic Bursting nukes and enfeebling magic. If you want more INT for less chance of a resist and more damage then eat a creampuff or have some brain stew. That should help these legs shine in any race exponentially.
The best leg piece for a BLM by far. The only piece than can match the MAB+5 is Morrigan's Slops but even then you're looking at a loss of 5 MAC which will hugely affect your resist rate. Only bad thing about these is getting the Cursed Trews -1 Clothcraft 97, gotta be 1 lucky SoB =]
MACC is a garbage stat but for pure damage these are the top piece in the game without question. If you have access to a pair you're probably seeing very diminished returns on INT and they will beat Morrigan's damage easily. Resist-wise on some HNMs you will need to stick to an INT piece but in most cases (for tarus at least) you can use these without issue.