Ranking the power gaps needed for...

My ranking from easiest to hardest (generally speaking);

Defeating through a haxx ability (e.g. Nihilus vs. Katarr)
Beating through conventional Force power alone when they're armed, without environmental advantage (e.g. Sidious vs. Yoda)
Overwhelming defenses with Force lightning (e.g. nearly Sidious vs. Yoda)
Beating through telekinesis alone when they're unarmed, without environmental advantage (e.g. Vaylin vs. Outlander)
Pinning with an initial advantage and holding them there (e.g. Luke vs. Caedus)
Ragdolling through Force barrier (e.g. Yoda vs. Ventress)
Oneshotting through defenses with TK (Possibly implied from ragdolling)
Telepathically dominating mid-fight against prepared defenses (e.g. Vitiate vs. Revan and Malak)
Successfully essence transferring (?)

It seems like different kinds of attacks need different power gaps to pull off against a prepared defender.

Sidious's lightning is particularly OP because it can come close to outright overpowering an equal, e.g. Yoda.