I love the contests and wish they would come back. It gives you something very different to do that can become an alternative path to raise pokemon for. It was very satisfying for me to annihilate npcs in Emerald with a Jigglypuff in toughness contests and give interviews afterwards.
I think contests are a great idea that I would like to see them continue to develop. Perhaps in later generations they will add components that closer resemble the anime.
I think RSE was a good introduction to contests yet I enjoy basically how they evolved in later generations. One thing I do miss from the original Hoenn games is berry blending. I am always up for a mini-game, and you had to get a fair score if you wanted a good quality pokeblock to give your pokemon. This tradition is continued in Sinnoh, where baking poffins are substituted instead, but I was a little sad that Oras took the game away. I preferred that my food could be a culinary masterpiece or burn if I made a mistake, rather than preparing itself magically with one click of the button.
I like the beautiful graphics of the Oras contests, and that they postponed getting your ribbon until you mastered rank and made you work harder in that respect. I also loved introducing Lisia as a new character that personalizes your adventures in the contests more. I would have liked a little more development, and seeing Wallace some more but still fun. Above else I love cosplay Pikachu, that is brilliant!
Overall though I think I might like Sinnoh Contests best, even though I have always preferred Hoenn as a region. Sinnoh contests have the most components, as with all contests you have to plan an appropriate moveset, win the audiences over with your enhanced condition and appeal with the right move at the right time. How you cooked still mattered back then though too, and on top of that Sinnoh introduced a dance phase of the talent competion. You also had to collect accessories and dress up your Pokemon to look good.
With trainer customization being a introduced in gen 6 I think fashion was more important than ever in the world of Pokemon and would have liked to have styled other Pokemon in Oras for contests just like you can style a Furfrou. Or at least let us decorate them with the fashion case again. Would not mind being able to pick clothes for myself either.
Who knows? Maybe when when we get Diamond and pass remakes we some of that will come to pass...