Suggestion to rework Demon Form and make it a toggleable skill

There are two versions of Demon Form in the game: one limited to 10 stacks and one unlimited. I would like to talk about the first one.

I believe that the penalty for using the form and the way it works needs to be changed to make this skill much more convenient and fun. The current implementation has a number of issues, some of which are related to bugs, such as: the form is canceled when reviving a teammate, when opening a stash or portal, as well as when loading between locations or triggering specific animations (some of the bugs have already been fixed in previous leagues, but they have reappeared in this one). The skill's cooldown also adds inconvenience. Even if there weren't these frustrating bugs, the cooldown would still hinder the combination of different abilities.

I would like to suggest making the form toggleable, as is done with skills such as Summon Infernal Hound. The penalty for use could also be replaced, for example, by replacing the gradual loss of life with a loss of life when killing enemies. Alternatively, a life cost could be added to skills' cost, or/and a system similar to Indigon could be implemented.
There are many ways to change the penalty and add flexibility to the skill, such as adding less life recovery for each stack. I think that this would not only open up new possibilities for builds (such as combinations with Chaos Inoculation), but also just increase a positive experience of using the ability. After all, Demon Form has an excellent visual and sound design, and I would like the use of this ability to be enjoyable too rather than being annoying and clunky, all while motivating the creation of diverse builds.

Thank you for reading