Doesn't Meg get ORKO by some laguz in her join chapter? Maybe it's just the bosses...she's not unusable, but unlike Edward (ya I know many ppl don't like Edward that much but I find him usable) and Nolan, she doesn't have that very early-game impetus to use her that just comes from being one of the few units available. Aran, a soldier, outclasses her in just about every way including durability. Though it's true he grows speed slowly, BEXP can fix that. She has swords, which is probably useful given her low base skill, but it would've been better to just give her a few more points in skill and lances probably. Again, she's definitely not unusable, I have actually used her, but there just isn't anything IMO that makes it worth investing in her. And she also has that movement issue.