Nah I wouldn't say weapon enchants are useless, but they sure ain't as important. Full heirloom gear is more than enough to stomp leveling. If you have an enchanting toon, you can get the dancing steel enchants for free basically nowdays, and the proc is quite strong. I usually settle for that.
As for lvl 100, no one actually does a different enchanting set for ChiExplosion spec. Multistrike enchants everywhere+haste on weapon is close to bis in every situation. According to Hinalover, come 6.2 switching enchants to multistrike might be equivalent or better with high gear.
I've been changing a couple things in my playstyle and getting good results damage wise. Mostly TeB management, if I get anything solid I'll post about it.
As for weapons, we've said it many times, there is a question about stats, about 2H vs 1H, but overall it realy comes down first to weapon ilvl.