You don't know how happy it makes me to see someone actually using the correct name for Gen 2's E4, instead of "Johto E4" (which does NOT exist, as neither Kanto or Johto have their own E4).
Anyways...
Sinnoh has always gotten props for actually using different types from previous games' E4s (unlike, say, Hoenn), but unfortunately, the awful Pokédex in DP held most of them back from their full potential. Luckily, Platinum came around and fixed that issue, and the Sinnoh E4 became one of the strongest E4s to ever appear in the games. They all used a variety of Pokémon from within their type (no more filling space with dupes/NFEs/other types), and they all had excellent movesets and strategies. They were also some of the first E4 members to actually appear outside of their rooms and get actual backstories and characterizations. Platinum should probably be the gold standard on how to handle an E4, IMO.
And, now we go from one of the best E4s to one of the worst...
The Gen 2 E4 has always sucked, period. Even in GSC, they were a noticeable step down from Gen 1, with their laughably low levels, mediocre teams, and the simple fact that they kept the always pathetic Bruno and dumped RBY's best E4 member (Lorelei) for some clown in a dumb mask and terrible Pokémon (Xatu as your ace,
really?). Coming right off the heels of Platinum's superb E4 only made them look worse in HGSS, which unlike Platinum, did
nothing to fix their teams from GSC.
ONLY Karen saves this E4 from being a complete failure like Hoenn's, and that's ONLY because of her quote, great design (only
in GSC, NOT HGSS), and decent team.
So, in the end:
Love: Sinnoh E4 and Karen
Hate: Rest of Gen 2 E4