A 6 kg model would need to be quite large to have a flying advantage over a 5 kg model in any environment. Many guys mistakenly think a highly loaded model handles wind better. A highly loaded model or any plane for that matter, just doesn't damp as quickly as a lower loaded one. The higher loaded model's total flight envelope is worse than that of a lower loaded model. If one has ever attempted a knife edge loop or a rolling loop, you'll know what I mean, but actually every maneuver suffers on a pachyderm

As far as power goes, electric is pushing 3.5KW in the better set-ups. It won't be long with battery advances that are coming to be pushing 4 KW...that's well over 5 HP. These will make weight too. Won't be cheap but top guys will "buy" them and lower tier guys will follow. Are these necessary? No. But that's progress.

Hell, I'm in process of stuffing DLE 55 on pipe in 2 m pattern plane. Weight is comparable to some electrics. Juuuust a couple ounces over 11#. That's 6 HP and overkill but why not. The 2 m is larger than the rest areawise. No tinsy weensy little winglets on this bird.