Can I ask the specifics of your latias Set. I have tried using 252spe 252hp CM/Roost/Sub/Dpulse on offense. I just found it did not hit hard enough for an offense teama and had kinda bad results. However more agressive sets seemed unable to reliably check keldeo. Maybe I was just misplaying.
One thing I like about weatherless teams is you can get really beautiful type charts. Stuff like double resisting every type (maybe sans ghost or something not important) and having no triple weaks. This sort of thing makes you much less vulnerable to late game scarf. This is very hard to do with weather teams.
For example the first team in your post does in fact double resist everything while having no triple weaks.