When WVU made the jump the B12 was definitely more stable, but I don't necessarily agree now. IIRC, the Big East finally increased its exit fee to an amount that will make departing members flinch a little. On the other hand, in the B12, Texas and Oklahoma can afford to leave at any time.
As a Big East fan, I don't feel great about a conference that's lost 3 key programs in the past year. As a B12 fan, I wouldn't feel great about a conference that's lost the same number over two years and could lose its two marquee programs at any time.