Ahsoka was intended to be a bit annoying at the start of her arc. That's why it's an arc. People that dismiss her just off that are ignoring the personal growth and journey that we are all on. No one was perfect when they were a teen.
The Clone Wars - despite some weird turns here and there - was amazing overall for character development that added a lot to the PT era. Ahsoka became one of the best realized characters in Star Wars through its run. Both new and old characters like the Clones, Maul, Anakin, Obi-Wan, Padme, Bo-Katan, and many others benefited with added depth, history, and their own journeys.
It's alright to not like it for personal reasons, of course. When some episodes missed the mark, they really missed the mark. But there are folks out there who just dismiss it outright which just feels unfortunate. The Siege of Mandalore arc alone is one of the best Star Wars stories realized on screen.