I think the word "bridezilla" should not be applied to confident women who know what they want and make choices.
It should be reserved for those women whose expectations for a wedding lead to entitlement and inconsideration for their loved ones' autonomy and for professionals' livelihoods.
For example:
- demanding a wedding photographer or makeup artist work for free
- demanding bridesmaids lose weight, dye or cut their hair etc because "it looks better in wedding photos"
- demanding gifts only over a certain monetary amount (I have literally seen people say if a gift is less than $500 it doesn't count)
- getting angry that a bridesmaid got pregnant and expecting them to have put their family plans on hold so that they would look better in wedding photos
- not allowing same sex plus-ones because it will offend conservative relatives
- obsessing so much over the details of a wedding that they forget to enjoy the actual wedding
- verbally abusing service professionals or their friends and family if something goes wrong
etc.