Here's my two cents on the matter. I agree with you that prototyping is necessary in some cases (wow-ing clients, expressing the behavioral details of an app, etc). In my experience, prototyping has been very useful, but I've done it in one of two ways:
Rapid Prototyping (my favorite). We're currently working on an Angular app and it's something I've picked up relatively easily. You're essentially prototyping using the framework your devs are working with in the very same environment your app exists in. Reasons (in my opinion) why this approach is best:
- High degree of code re-usability (provided you're not using throwaway code - see Adobe Muse spaghetti code factory).
- Ability to demonstrate the true behavior of the app/feature by using the same framework as your devs,
- Experience the pain you might put your devs through by asking/designing animations/behavior that can sometimes prove to be unnecessary and expensive to build. I'm not saying this is the case in your situation, but it's worth mentioning.
I still do this to put together simpler features and behaviors which do not require too much effort. This for me is the go-to method if I have time and the feature is not too cumbersome to digest/explain. I use Invision to help with simulating behavior and Sketch for the designs.
I'm not sure if either of the above will do the trick for you, but I can tell you they may be less time consuming than using After Effects (relative to your level of proficiency with AE of course). If you already have the designs ready and the behavior you're trying to elicit can be accomplished with any the following tools, I would recommend (in no particular order):
- Sketch Prototyping by using their Craft plugin. Proto is still in beta, but you can request a code from them. It's pretty solid.
- Adobe XD
I hope this helps with your decision.