Why do you think gen-specific Pokemon pairs get unequal treatment by Game Freak? (Eg, Vileplume got a new evolution in Gen 2, while Victreebel got nothing, and Whimsicott was already better than Lilligant even before becoming Fairy-type in Gen 6.)
I suppose because those pairings don’t serve any gameplay purpose beyond the games in which they were originally introduced. Oddish and Bellsprout were no longer version-exclusive in generation II, so why continue to act as if they were? If anything, I think it would be pointlessly restrictive for future games to demand that those pairs of Pokémon continue to mirror each other. If you have an idea for an alternate evolution for Gloom that you think is a good one, why declare it invalid because you don’t have an idea for Weepinbell? As for Whimsicott getting a buff that Lilligant missed out on by becoming a Fairy-type – well, you’ve hit the nail on the head. Whimsicott was already better than Lilligant, so clearly they didn’t care in the first place. Why would they care more in generation VI, when Whimsicott’s special relationship with Lilligant was no longer relevant, than they had in V?
Trend is a bit too strong a word, but I’ve noticed in your reviews of new Pokemon, specifically version-exclusive Pokemon, you tend to prefer one over the other. Cf Cottonee/Petilil, Solosis/Gothita, Clauncher/Skrelp. Would you care to talk about the implications of version exclusivity at all? (I mean, beyond the natural selling point of forcing people either to make new friends or buy two versions of the same game.)
Well, I talked a little about this here, and honestly I tried to think of some point to it beyond driving more sales, but didn’t come up with anything. In gameplay terms I think that particular aspect of the paired-game concept is obsolete, because version-exclusive Pokémon are among the smallest obstacles to finishing a Pokédex today. So is there anything else to it? I suppose it would be something if you could argue that the sets of version-exclusive Pokémon say something about the character of the games they appear on – like if you could say, for instance, that Ekans, Vileplume, Primeape, Arcanine, Scyther and Electabuzz somehow thematically “go with” Red/Fire/Charizard in a way that Sandslash, Victreebel, Persian, Ninetales, Pinsir and Magmar do not. And I think maybe you can almost say that for the Ruby and Sapphire sets, but you really have to stretch some of them to make it fit. Or perhaps you could conjecture that the different versions represent different seasons, or something along those lines, so that Red version represents the experience of a trainer who started a journey in winter rather than summer (that doesn’t work for generation V, of course, which actually has a season mechanic), or something else along those lines. In the end I really don’t think there’s much you can draw out of it.