Doing some angle weighted leg raises once or twice a week isn't bad at all!
I also find it bith more effective and easier to do X number of weighted ab exercises than 100 situos or 50 leg raises. Even just putting a couple 2.5 or 5 lb ankle weights on leg raises adds up fast due to the leverage.
Abs do suck though. I purposefully do them in the middle of my routine otherwise if I wait til the very end I will be like "eh, fuck it" and either only do a set or two or just skip them haha. My abs are good and look good, but I am big in core strength.