Just for a bit of nitpicking--There is NO such thing as a "Kanto Elite Four" or "Johto Elite Four." The two regions share the same E4 at the same Indigo Plateau, and any differences between Gens 1 and 2 can be chalked up to the passage of time, not the existence of a separate "Johto Elite Four." (If you were to go through Johto at the time of Gen 1, you would've still fought the same E4 of the original games at the end, not the one from GSC.) It's better to say "Gen 1 Elite Four" and "Gen 2 Elite Four" ("Indigo Elite Four" for both).
Anyways...
I was actually discussing this with a friend a little earlier, and he pointed this exact same thing out (and said it was the reason why he hated Hoenn's E4). For only being three Generations into franchise at the time, it looks very suspicious (and unoriginal) that they would pick four types that had already been used at Indigo for the Hoenn Elite Four, even going so far as to put the Dragon trainer at the top of the pile again. It was inevitable that Hoenn would repeat type specialists (all but one of the 17 types were already used as gyms in the previous Gen), but they could've done better with the Elite Four. (Especially, Glacia. Why would they put an Ice specialist in a region that only had two fully-evolved Ice types? One of which was a complete piece of crap?)
I say this looks suspicious, because I can't help but wonder if Hoenn's E4 was meant to be a hint towards FRLG--We had Ghost, Ice, and Dragon again, with the Dragon user in the 4th position. The Ice user also looked suspiciously like a younger version of Gen 1's Ghost user.
You can see similar remake hints in Sinnoh and Kalos. Sinnoh's Ground user, of course, resembled Agatha, and more importantly, its Psychic user strongly resembled Gen 2's Psychic user (the only other Psychic E4 member that existed at the time). As for Kalos, it had Water and Steel Elite Four Members, marking the first time since Gen 3 that either of those types had been seen in the League (albeit on Champions). The Water user also happened to be a frilly, effeminate-looking young man with a White/Blue color scheme (again).
And, speaking of Kalos, there could possibly be other remake hints in its E4. It's two female E4 members can be seen as parallels to the two female E4 members from the original games.
Lorelei and Malva are both bespectacled young redheads who happen to be the only E4 members seen outside of their rooms in their respective games, but while Lorelei uses Ice/Water types, has a cool personality, and fights against evil, Malva uses Fire types, has a hot personality, and fights for evil.
Agatha and Drasna are both older women in long skirts (and with long, grey hair if you go by Agatha's original design), but while Agatha is creepy, hateful, and competitive, Drasna is inviting, friendly, and humble. Ghost (Agatha) and Dragon (Drasna) can also be seen as parallel types--both weak against themselves, both resisted by only one type (Dark vs Steel), both made immune by one type (Normal vs Fairy), both had only a single 3-stage evolutionary line in Gen 1 (Gastly line vs Dratini line), both didn't receive STAB moves until Gen 2 (Shadow Ball vs Dragonbreath; both Gym Leader TMs given out by the 4th and 8th leaders, respectively), and both suffered from mismatched Pokémon before the P/S split (Ghost was a Physical type with mainly Special attackers; Dragon was a Special type with mainly Physical attackers). Drasna's pre-battle rematch dialog also refers to the region that introduced another E4 member that paralleled Agatha.
Lorelei would've been better, as Agatha's team was mostly Poison thanks to the lack of Ghost types in the original games (and the only ones that existed were all part-Poison themselves). Of course, there was going to be some GL/E4 overlap with Gen 2, as all of the types (sans Dark) were represented in the 16 gyms.