I beat the Kanto Elite 4 just yesterday, and my team was around level 47. Btw, you basicly just said the team on your signature. Way to self-promote~~ (why would people copy your team? If you said strategies, then **** yeah, but just team members? This works good adainst this, that works good against it... I mean, come on...).
Now, seriously, how is aerodactyl good against Lance? His Gyarados can take a couple of rock slides and kill with anything water/thunder. Alakazam, if you're underleveled, gets outsped by Gengar. And when you're as frail as Zam, that isn't good.
Lapras is good. Bulky as ****. Can't handle the elite four though, since he gets outsped by the DNite (thunder), the gyarados (thunder), Bruno's team aside from the Onixes and besides tanking ****, there isn't much to it.
Venusaur is also good, but before being water, Lorelei is also ice.
The Hitmons are good too and granted they'll kill off Lorelei easy, but they can't touch 2/5 of Bruno, Agatha as a whole, Lance and all his flying types and the only thing he can do to Gary is kill off Rhydon.
If you go with raw power, then that team isn't ideal. I'd say most here don't have friends with GBAs and GBALinks to trade the Gengar/Zam with. And who the hell would have the patience to train up an Aerodactyl in time for the E4's first run? I mean, he's only lvl 5 when you get him in Cinnabar, so...
My point is, if you just go with raw power, then you need to grind. A lot. Like I said, using your head is the best method, and in most cases, you can run these strategies with many pokés:
My team/strategies (most taken from competitive):
Venusaur is the perfect sun-abuser. Better than him only Exeggcute, since he has clorophyll, and that + Solar Beam = Win. Wouldn't have mattered though, since outsped most things in that place anyway.
I used Ninetales (also as a sun-abuser) to aid Venusaur in though kills, and my Dodrio (toxic staller) with Will-O-Wisp and Confuse Ray. He also killed alot of **** with flamethrower + Venusaur's sunny day.
My Dodrio was the guy who taunted all things. Then he toxic'd, and protected, and then he taunted again, and then proceeded to murder them with fly.
Other very common meta strategy is sand veil. Sandslash + Double Team (or anything with sand viel, really, + sandstorm) works pretty well in most cases, and if you kept the move, rock tombing Agathas Gengars to get them to low as sin speed is essencial.
They can't touch you, and they're now too slow to do anything to the rest of your team. That + EQ was how I dealed with Agatha as a whole. That and my Snorlax, who is just a normal RestTalk tank (good since Gengar has Hypnosis, and rest talk is already asleep anyway. Beware of Dream Eater though) and killed the gengars with Psychic (Snorlax's movepool is vast).
My other team member was Gyarados (plain out sweeper here, coverage and ****) and
he was the one to both save me and cause me the most trouble - since he was the only one using raw force - and a Thunderbolt from mine does barely over half to Gary's Gyarados. Blizzard also does only barely over half to Lance's DNite. BOOO Special/Physical split not happening.
Anyway, those strategies I suggested (most with pokémon rarely used) conquered the E4 without many issues really, and all at lvl 47. They can be used with other pokés:
Replace Venusaur with Exeggcute and you get better coverage, Sandslash with Marowak or Digglet and you get more raw power, Snorlax with Chansey just for tankish purposes and healing without needing to fall asleep, though worse coverage and power, Ninetales with --insert fire type here--, Gyarados for any classy water type since he can't use his great attack stat if you're not running Bounce or... Strength, and Dodrio with Fearow, since Fearow>FEARon, and he also gets taunt, toxic (everyone does) and can deal with **** better. Shame for no Tri Attack though, but the stats are better, I'd say.