Well... Latios does function as a good stallbreaker, so I suggest that we run a balanced offense team around it.
Latios is rather similar to Arceus-Dragon in that it will struggle with scarfed dragons, especially physically based ones like Zekrom and Rayquaza, so a good defensive Steel type should work (maybe Ferrothorn? they have nice synergy. gotta watch out for V-Create though...). Lustrous Orb Palkia can also help in abusing weather, with access to Hydro Pump, Thunder, and Fire Blast, but can also function without it, with its STAB Dragon-type moves. Lastly, it will be walled by Ferrothorn in rain, so a Fighting-type like Terrakion or Arceus-Fighting may work (okay synergy here too I suppose), or Rayquaza with V-Create / another Fire move.