The combination of Poke Marts with Pokemon Centers is very convenient (with the combined building being a hub for "all things Pokemon" as mentioned earlier).. Although
Pokemon Ruby and Sapphire doubly introduced unique and iconic Poke Mart designs
and unique Poke Mart music that even went as far to become used in Generations 4 and 5 (as far as I know), I would rather have the Poke Marts depreciated and moved inside the Pokemon Centers.
As for the music, I imagine that it'll play triumphantly in Lilycove Department Store. If clothing stores take the place of the areas of Hoenn's Poke Marts, they could make could good use of the Poke Mart music since they primarily serve as places for the player to go shopping!
Does anyone know what music the various clothing stores of Kalos used? Since fewer Hoenn locations may use the Poke Mart music, the Pretty Petal Flower Shop (near south of Rustboro City) and the Lavaridge Town Herb Shop, both of which re-used standard town/city music if I recall correctly, could put the Hoenn Poke Mart theme to better use! Similarly, that treehouse in Fortree City that sells the player some Secret Base decorations (like Desks and Chairs) could also use the Hoenn Poke Mart music.
*I always imagined that even if the Poke Marts were moved inside Pokemon Centers, there would be certain tiles (maybe blue-colored, to represent the Poke Mart color) you could step on (or maybe the Mart sellers would be secluded in a mini-room/hallway behind a translucent pretty glass panel or something) that would switch to the Poke Mart music for the time that you're on those specific tiles (like how music changes when moving between different buildings/Routes/cities and towns)..
I honestly hope to see those lil' blue devils everywhere, again. I mean, Ruby and Sapphire WERE the games that gave the PokeMarts a specific look to them. I love the mart being inside of the Center, don't get me wrong, but I've always liked the thought of them being separate places, and I miss all the people inside of the PokeMarts who would tell you useless hints and tips lol
Maybe all of those "tips" people could be moved inside the Pokemon Center? Although that would be a lot of people within one building.. XD
I doubt it. Although the originals brought us Mart music for once, I don't foresee it returning. The change was made for the better and I think they'll keep it. If not, I don't really mind because I sometimes still walk out of the PC and forget the shop is there haha.
{XD} I think I'll being doing this at some point since I'm so used to Generation 3 Poke Mart layouts. XD
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Oldale Town is going to be really awkward now.. I'm guessing a clothing store or random NPC house will replace the Oldale Poke Mart, but the "follow me" lady will have to mosey on over to the Pokemon Center now (which seems even closer XD).