SUMMARY: So now that the show is in Disney+ in Italy, France, Germany and the Netherlands, i through that i could add more ideas in case that a second season is announced, so this is what i have.
1- Introduce a Doberman character, who acts tough and scares anyone who gets in their way, but in reality he is has a hobby that they likes in secret, they don't like to show it out of fear, only for Dylan, Da Vinci or DJ, find out and then convince them to stop hiding it, becoming friends.
2- I would like that the show have a wolfdog, as i want a plot that involves solving a mystery about a monster that has been showing up in the woods recently, Dolly wanting to find out is the rumors are true goes to investigate, Dylan scared that something will happen to her goes to, they got lost and gets scared when night falls, so when the monster appears, they both run, only to came up with a plan, which works only to discover that is a wolfdog who has been scavenging food for their mate who had a litter, so Dylan and Dolly apologize to them.
3- I think an episode that involves Dylan meeting a stray cat, at the beggining Dylan fears them, as the cat's fur is black who are rumored to cause bad luck, also the fact that Dylan had bad experinces with them and having allergies, so he wants to avoid them, only to lost Dorothy in a trip to the park, he fears the worst only to discover that the cat actually found her and is genuine in wanting to be friends with Dylan.
4- After seeing ChelleDoggo's OC Bea, i want that the show have puppies of different breeds, who are not only friends of the Dalmatian family, but they are seen as siblings to them, mostly because i would like to see them going in adventures with Dylan and Dolly, and spent time with Doug and Delilah to give them more spotlight.
5- Have human characters who are friends of the Dalmatian family, they would be a group of friends who not only likes to care for them at the park, but hang out with them in a regular basis, they could be a geeky character, a jock, a biker and even a ballerina, but only teenagers as it would be better for the story.
6- Having more animals, i would like to see a rabbit who acts quick witted but thens to be reckless, a mink the despite being elegant gets angry and a bat that despite looking scary is actually a softie.
7- A new villain for a new story arc, one who seeks the help Cruella in her plan to get revenge, but this time by finding a way to take their house, that would cause them to end in the street, this will cause the Dalmatians to seek help from other humans, that turns out to be the descendants of Roger and Anita, it would be great to introduce more of the lore in the show.
8- Have us introduce more members of the Dalmatian family, at least a family tree, this could be addresed in an episode where Dylan and Dolly explore their family story and discover about what happened after the events of the original movie.
9- Having a posse of purebred dogs who acts as rivals to some of the younger siblings of the Dalmatian family, despite being snobs who believe they are better than them, they are insecure deep down and just want to accepted by everyone.
10- Make a new horse character that is a rookie Pearl's training, unlike her she basically wants to be an action hero who doesn't follow the rules, and becomes friends with Dolly sometimes being a sidekick in her adventures.