I have been looking for an online task planning solution for some time. Best sofar was www.prosoar.de - but sadly lacking any waypoint management. Crosscountry.aero seems to be filling the gaps between skylines.aero, prosoar.de and seeyou cloud.

I just applied for a demo account and got a first impression. Waypoint management looks good. Task planning is currently useless since no airspace is available (as far as I can see). Nonetheless, this looks promising and will hopefully evolve into a desktop seeyou/strepla replacement.