The 3.7.0 expansion, due in June, will focus on improving animations and adjusting the numbers behind certain melee skills, but the dev team are also currently "experimenting" with changes to accuracy, feedback for hitting and missing in melee, melee splash damage, leech, fortify, melee base types, movement skills and the melee damage tied to certain items.
They are also working on changes to "various Ascendancy classes" as well as the passive skill tree, they said in a forum post.
"Players from other Action RPGs have occasionally criticised Path of Exile's melee combat for being 'clunky', especially early on before players get a lot of attack speed," they said. "We are making various experimental changes to the animation system that should help resolve these concerns and really tighten up the feel of melee combat."
The full announcement of the 3.7.0 expansion will happen next month, at which point Grinding Gear will reveal more details about the planned changes.