First off, they would be in no way obligated to remake the first gen again. That doesn't fit into the pattern they have going as far as remakes are concerned.
First gen
Second gen
Third gen -> Remade first gen
Fourth gen -> Remade second gen
Fifth gen (on the same console as four previous games
) -> Time to remake the third gen
This pattern will likely continue until they hit the point that a remake won't change how the game looks and the amount of content substantially.
tl;dr - A remake would be the opposite of surprising.
On a personal note, I loved Sapphire. It was the first Pokemon game I actually bought with my own money, and I've beaten it many times.
Never saw why people enjoyed the third gen. I would consider it the worst gen.
It felt like a completely step down. Gold, Silver, and Crystal introduced a new continent but also allowed you to play with the old one. 16 badges and a trip down memory lane. Plus the Pokemon were good and still fresh in design. Then RSE came along and the Pokemon designs seemed kinda boring and forgettable and they stepped back to 8 badges. Also, I never saw the point of "secret bases". They became completely pointless it seemed. You add a few fun slides and Pokemon dolls and that's about it. It's not really fun or necessary. Plus the "overworld" never seemed massive compared to the dual continents of GSC.
Also, why request a remake for a game that seems fundamentally the same for every game, mechanics wise? I'd want to encourage something new or want them to improve upon the formula more, not take a step back for another remake.
The 16 badges of GSC and the return to Kanto was a poor move to me. The Kanto region felt so stripped down that they might as well have put the eight gyms side by side with Red sitting next to the eighth. It was nothing but filler if you didn't feel the actual game was long enough. I can't say I was able to really appreciate that portion. In fact, every time I've played, I've never completed the Kanto portion, as it is just so damn boring compared to core Johto portion.
I consider the second gen the experimental stage. Yeah, it was the best in terms of new content. Pearl/Diamond and Black/White are even a step down when comparing core aspects like the actual Pokemon. It was early, and there was room for creativity. Once you have two generations of the fuckers, I'm sure it is a bit more difficult to come up with new stuff continously, yet the fans will demand it endlessly.
The step down to 8 badges was a move of "we have enough content here, lets not push the patience of the players." I liked a lot of the Pokemon. I liked them a lot more than I like anything that has come since. The secret bases were more of a "we hope you have friends that like Pokemon deal." I'm sure they worked out great in Japan, but had limited success elsewhere. I will argue that the overworld was massive (underwater caverns and shit, big land masses, lots of ocean). Comparing the map in GSC to the map in RSE is like comparing the size of Australia to the size of the whole of Asia. Doesn't compare by much. The earlier maps were generally just elaborate loops due to the limitations of the hardware, while later maps send you on a one way road with a few shortcuts here or there to help you out, but going backwards isn't easy without the Fly ability.
Pokemon fans like dem remakes.