Yeah, but he couldn't do anything, he was being held in midair.
And what's stopping Vader from doing the same? Being 80% of OT Sidious grants you immense force powers.
Well, RODV does.
It takes place right after RODV. By this time he would be a bit more used to the suit.
And remember, this OT Vader has an extra 20 years of Sith training.
He had a galaxy to run. he had no time to train an apprentice from an infant, like he did with Maul.
Maybe not, but he still left most of the governing to the Moffs, the Admirals and Vader. He devoted alot of his time to the Dark Side, considering he wrote three huge Dark Side encyclopedias. And he also supervised and trained these Dark Jedi:
(kudos to Darth_Glentract)
Gwellib Ap-Llewff, Dark Side Adept of the Imperial Citadel
Argor, Lesser Prophet of the Dark Side
Boc Aseca, Dark Jedi
Picaroon C. Boodle, Dark Jedi
Brakiss, Apprentice Inquisitor
Adalric Cessius Brandl, High Inquisitor
Jaalib Brandl, Apprentice Inquisitor
Shira Ellan Colla Brie, Emperor's Hand
Joruus C'baoth, Guardian of Wayland
The Cloaked Figure, Lesser Prophet of the Dark Side
The Constable of Homunculi, Clone Keeper
Cronal, Lesser Prophet of the Dark Side/Emperor's Hand
Sa Cuis, Emperor's Hand
Ameesa Darys, Inquisitor
Nial Declann, Grand Admiral
Drayneen, Inquisitor
Jeng Droga, Emperor's Hand
Durrei, Dark Jedi
Baddon Fass, Dark Side Elite
Flint, Stormtrooper
Vill Goir, Dark Side Elite
Gorc, Dark Jedi
Gornash, Lesser Prophet of the Dark Side
Kvag Gthull, Dark Side Elite
Halmere, High Inquisitor
Hethrir, Imperial Procurator of Justice
Roganda Ismaren, Emperor's Hand
Mara Jade, Emperor's Hand
Shela Jalahafi, Dark Side Adept
Teles Jalahafi, Dark Side Adept
Carnor Jax, Imperial Sovereign Protector
Jedgar, High Prophet of the Dark Side
Jerec, Inquisitor/Emperor's Hand
Kadann, Supreme Prophet of the Dark Side
Zasm Katth, Dark Side Elite
Danaan Kerr, Dark Jedi
Vess Kogo, Emperor's Hand
Arden Lyn, Emperor's Hand
Malorum, Inquisitor
Maw, Dark Jedi
Merilli, Lesser Prophetess of the Dark Side
Krdys Mordi, Dark Side Elite
Morthul, Dark Jedi
Nefta, Dark Side Adept of the Byss Clone Vats
Xecr Nist, Dark Side Elite
Quarmall, Dark Jedi
Sarcev Quest, Emperor's Hand
Loam Redge, Inquisitor
Rillao, Dark Jedi
Sa-Di, Dark Side Adept of the Byss Clone Vats
Sancor, Inquisitor
Sariss, Lesser Prophetess of the Dark Side
Sedriss, Dark Side Elite
Shynne, Inquisitor
Mox Slosin, High Inquisitor
Kam Solusar, Dark Side Elite
Maarek Stele, Emperor's Reach/Emperor's Hand
Tedryn-Sha, Dark Side Elite
Savuud Thimram, Dark Side Adept of the Imperial Citadel
T'iaz, Dark Jedi
Laddinare Torbin, Grand Inquisitor
Tremayne, High Inquisitor
Vost Tyne, Admiral
Valytar, Inquisitor
Vialco, Apprentice Inquisitor
Yun, Dark Jedi
And Vader was a big bit above all of them. Granted, they might not have been powerful than the "uberhero" tier characters (Obi-Wan, Anakin, Mace, Yoda, Dooku, Sidious), they were Dark Jedi.