Would you be more specific as to why you prefer flask to django?
I looked at flask, and the code for views doesn't look much different. It does look like it's missing form and model validation. Do you use a library for that or do you not do that?
For forms, the usual solution is WTForms library with the help of flask-wtf extension glue that provides Flask-specific convenience functionality.
Flask has somewhat minimalistic core, with significantly less batteries included, compared to Django, and this gives somewhat more freedom in choices of components.
This was more true when Django was less mature (0.9x and early 1.x times), when a lot of things were much less flexible there, while Flask had somewhat more active community than it has today... but it probably still holds.
I believe, both are great frameworks. What to use depends on what one wants to build, how well it aligns with the framework's assumptions and "best practices", and one's personal affinities.
I looked at flask, and the code for views doesn't look much different. It does look like it's missing form and model validation. Do you use a library for that or do you not do that?