Sharing power and being so generous with it is a wonderful message, but the nature of that power (which stems from a demonic spirit and is routed in darkness) requires a greater responsibility and guidance than I believe Buffy and her friends are capable of providing. And it's something the world at large will view with fear and suspicion. Recall that only 500 slayers are working with Buffy and the other 1300 are at large and quite possibly abusing their power without a mission to center there new powers.
There's also the point that keeps resonating from the LWH through ToYL about how things are not always as they seem and foreshadowing that strength and hubris leads to your downfall. This best relates to Willow's statement that slayers don't draw strength from their numbers the way vampires do, a criticism that both Giles and Buffy express in The Long Way Home about the girls not "working together". What if the nature of the slayer power is actually weakened by it being spread too thin amongst so many girls rather than concentrated in one champion?
It all seems to be pointing to the negative consequences of the Slayer Spell in Chosen (which has been alluded to as fascism in The Chain - fascism...yay?). There's no simple right or wrong as Xander tells us in A Beautiful Sunset that the girls in Buffy's squad are positively vibrating with purpose and connection. That it's a positive energy. And it *is* - but that's only 50 girls out of 1800. Let's say that the other 450 slayers working with Buffy are also a force for good - we're still left to wonder how many others are out in the world and possibly faltering or unable to deal with their new nature because they lack the proper guidance.
So it seems like the Slayer Spell and the world it's created at best exist in a gray area and I'm expecting this situation to continue devolving into the negative as the season progresses. It seems like we're going back to a world where there's only one slayer. But there's a final twist. A huge theme introduced in LWH is that things are not as they seem - maybe we're building momentum towards the world needing to go back to just one slayer to restore the balance. But maybe there's a Hail Mary pass left for the final moments of the season and the positive message of sharing power won't be sacrificed - I'm not sure how this could happen, but I have faith Joss could surprise me. However, we can't ignore the fact that maybe, just maybe the gift Buffy shared with 1800 girls should have included a receipt. Is it time to cash it in for world save-age?