I grew up there so am probably biased, but I love it. Valletta is my favourite part, just a beautiful historic city with so much to see and so many lovely cafes and restaurants to sit outside in the evening.
Mdina was used as a set in Game of Thrones, it is a medieval walled city and is so atmospheric in the evening as the sun sets.
Hal Saflieni, Mnajdra and Ggantija are UNESCO world heritage sites, again cannot believe people have visited them and not been impressed - much more extensive than Stonehenge.
There are sandy beaches, like Little Armier Bay. If you go to Mellieha/Golden Bay in high season then yes it will be pretty busy, just as Bournemouth beach is in summer. We pick a hotel with a good pool and private access to the sea (via steps from the rocks), and our kids are more than happy with that (all day every day).
Better beaches and quieter island life on Gozo - which is very similar to going to a quiet Greek Island.
St Julian’s is a shithole and always has been, I agree you should stay well clear of it. It’s been overdeveloped and is a cheap AI destination so you get a lot of drunks. Whoever upthread said Blackpool had it about right. But it is very easy to avoid.
Maltese people love children - DS had a massive fuss made of him everywhere we went, special teddy-shaped pizzas in one place (definitely not on the menu), free ice pop in another, huge fuss of him made by the horse cab drivers (got to feed a horse himself). Museum attendants bending down to ask him about his dinosaur toys. All completely unprompted and lovely.