[2019] Here's a short comparison video that shows how far behind a Warlock's melee speed falls compared to other classes.

Spoilers: It falls significantly behind.

https://streamable.com/dn2bp

This was done by smashing the melee button until five melees were performed with each class. The more melees you do, the further behind warlocks fall. This is a pretty egregious issue considering all classes have the same melee range. It means you are out of luck the moment you engage in a melee fight with anyone except another Warlock.

But no enemies are being hit in that video. Does this apply to actual melee fights?

The answer is yes.

https://streamable.com/5a1k4

Will this be fixed next season?

One can hope.

Edit: For the nth time, all classes in D2 have the same melee range. Handheld Supernova is not a melee.

In case the links don't work, u/pisshorse made gifv mirrors.