Actually I like the ones involving a special theme, such as time, space, life, death, that kind of stuff. Those guys make sense to be a god-Pokémon. You'd think they're going to run out of ideas at some point, but the S/M legends are really cool.
I would just love to see what Pokémon live in space. We have Clefairy, Solrock and Lunatone and Deoxys, Jirachi and Rayquaza as legends confirmed, but that can't be everything. There must be some really cool stuff out there and I wanna know what it is!
I must say I only played the original Hoenn games. How did space travel work there? Did it have something to do with the soaring thing with Latios/Latias?