Don't waste your money on a park hopper, just buy a third day if you're looking to spend that money and aren't hugely time constrained. Also wouldn't advise trying to do the parks from open to close, it's tough on adults and really wears you down with kids. Take a break during/after lunch time to recover and avoid the peak heat/crowds.
My 4 year old (with an annual pass) probably likes Hollywood Studios most right now, but he's always changing his mind. EPCOT isn't really that bad with evening drinking other than it can get congested on busy nights. AK is kind of a half day park in general unless you go all in on the zoo parts, but it's finally bringing back the full shows and character experiences which make it a little better.
Current favorites
Magic Kingdom: Mine train (get in line just before fireworks start if you can), Buzz Lightyear Space Ranger Spin, Monsters Laugh Floor, Dumbo playground
Hollywood Studios: Slinky Dog Dash, Toy Story Mania, Disney Jr Dance Party, Frozen Sing Along
EPCOT: Three Caballeros, Kidcot Showcase cards, Club Cool, video games after Spaceship Earth exit, playground
Animal Kingdom: Boneyard, Safari, Rapids
Current hot or cold
Magic Kingdom: Astro Orbiter (terrible ride but kids somehow like it), Peter Pan (overrated), It's a Small World
Hollywood Studios: Tower of Terror (loves it after he rides), Rise of Resistance, Lightning McQueen
EPCOT: Guardians of the Galaxy (preshow scares him, music too loud), Nemo (aging out)
AK: Kite tails
Current irrational fears/dislikes
MK: Dumbo ride
Hollywood: Star Tours, Mickey & Minnie's Railway (too loud)
Epcot: Frozen Ever After, Remy (heat and water splashing effects), harmonious fireworks show
AK: It's tough to be a bug