The best replacement for dormer is skylight.

The best alternatives to dormer are rated as following:
★★★★★  skylight
★★★  velux
★★★  mansard
★★  gable
★  dorper
★  velux windows
★  emilia clarke
★  no dormer
★  gable dormer

Your alternative for dormer is not listed? Suggest!
Speaking about dormer, one probably shouldn't forget about hip roof.

Other search terms related to dormer and their ratings are:
★★★★★ hip roof
★★ trusses
★ vaulted ceiling
You have in mind a companion for dormer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of dormer in all years. Click on graph for more.
dormer
skylight
velux