If we assume that all types of miles, points, and cash are equally valuable and useful to you - which is foolish, but you haven't given us any other details - then personally I would go for the flexperks now, because that's the highest bonus we've ever seen on that card, that I can recall.

Would probably next get the AA cards, since the bonuses are decent and it's not likely to see better before you could apply again. Might as well get the clock started.

As far as waiting, the BA card has offered 100k for two years now, so I'd wait on that until next year. I'm personally waiting on a higher Sapphire offer, since the targeted offers have been as high as 100k in the past. Have also seen higher offers for Delta cards.