Deadpool 2 works and the real secret to why it does is you. Well, maybe not you personally, but definitely the role additional dialogue replacement (ADR) plays in the film.
It is part and parcel with all filmmaking for the actors to dub (or loop) some of their lines after the fact to get a cleaner sound than whatever was recorded out in the field. This also requires them to synchronize lips and hit the same intonation and emotional resonance as their original performance. Other times, actors are called in to deliver new lines of exposition over transition scenes to plug plot holes. But very few films (live action or animated) can afford to almost completely rewrite the main character's dialogue after shooting is complete. Of course, most films don't include a hero whose mouth is completely masked for 90% of the film like Deadpool.
Ryan Reynolds has admitted that this was one of the keys to what made the first film work - he could record lines on his iPhone that he (or a writer) thought of later, send them to the editors, and then come in to do proper ADR recording if the line made the scene funnier. Not having to commit to a joke - or even a way of delivery - allows for an incredible amount of freedom on set when the physical elements of the scene feel right. It also provides the opportunity to try lines on test audiences, and rewrite them if necessary, tweaking everything until it runs like a finely tuned engine. And Deadpool 2 revs on all cylinders.
More than a superhero movie or summer action blockbuster, Deadpool 2, much like the original, is best enjoyed as a comedy. The people least likely to enjoy it, however, are those not familiar with superhero movie tropes, and those that slavishly enjoy said tropes. But for someone like me who almost begrudgingly goes to see each new installment, worried I might fall behind current pop culture cache, it was the shot of adrenaline I needed to counteract my superhero fatigue. One that comes, I should say, on the heels of four above-average Marvel movies in a row ( Spider-man: Homecoming, Thor: Ragnorok, Black Panther, and even Avengers: Infinity War). It took a movie like Deadpool 2 to not only make-fun of what drives me crazy about the never-ending parade of superhero films (the sense everything is always just going back to normal), but it actually embraced that absurdity, truly becoming a comic-book movie rather than pretending it's a drama with men in tights.
Characters like Zazie Beetz's Domino, whose superpower is that she's lucky, glides through chaos and carnage with impossible ease - reminding us that this is basically every superpower distilled into its most basic and ludicrous form. Deadpool himself, who can't die even when he tries to commit suicide, is equally living in a purgatory of a charmed life, trapped by the same fate as us viewers who can't seem to shake these comic-book movies. No matter how much we complain, we keep coming back. The post-credit sequence nailed the ridiculousness of it all best, and left me wanting to cheer as I stood up to leave.
Maybe you can add that in later.