I don't have much of a memory of Crossroads so maybe it was a slog too. Probably. I do remember Knife of Dreams being a sudden change of pace that moved along fairly briskly, because Jordan was dying at the time. It was a welcome change, but it honestly pissed me off that this joker had been faffing around for 3,000+ pages on purpose and could have written a better story anytime he wanted. That still pisses me off, actually. If Sanderson hadn't provided a brisk and serviceable trilogy to end the series I doubt I would have finished it.