Sorry, but without knowing the other applications and media you will be using, and the kinds of projects you will be making, it would be unwise to make a recommendation.
Go with the most storage and most ram you can afford.
One thing that worries me about your post:
... my old computer couldn't keep up with the performance especially editing videos in After Effects was very upsetting.
I don't know anyone with experience that uses After Effects for Editing Video... You should be using a non linear editor. The only thing you should be doing in AE is applying visual effects of motion graphics to individual shots that you can't do in your NLE. AE was never designed as a video editor. It's lousy at the job and none of the underlying architecture in the app was ever designed to function as a video editor. 90% of my AE comps are 7 seconds or less. Many of them have very complex structures and are layered with dozens of effects. It is not uncommon for me to create a comp that takes up to a minute a frame to render. I kind of draw the line at seven minutes per frame. Of course you can do simple things in AE and I have done several projects that take an average of just a few seconds a frame to render, but those are the exception.
On occasion you can efficiently work on short sequences in AE but it's a good idea to limit your sequences to a single line of dialogue or a single phrase in your music track.
My portable is the previous generation of MacBook Pro R 15 that is fully loaded. I plan on keeping it until January, when my Apple Care is half gone, selling it and ordering a new fully loaded MacBook Pro R 15. The total out of pocket will by about what it would cost for a middle of the line PC laptop because Mac's maintain a very high resale value if you are wise about your upgrades and plan your hardware purchases with the help of a solid business plan. It's all about the $$$ to me. Over the last 12 years I've spend about 1/4 as much keeping my Mac hardware current and running as I have spent on my PC's, so my recommendation, if you want to stick with Mac is to buy the most powerful one you can afford, then add on Apple Care and when you are about half way through your Apple Care program trade up. If history can be relied on will be money ahead in the long run.
Thanks for your answer, i'll be mainly using premiere for full HD or 2.7k videos. I'm trying to get some skills in editing videos besides color-correction and stuff. My goal is to be able to add effects and creating a "new video" out of the raw materials inrecorded. In after effects i'm really a beginner but i'd really like to learn working with this application.
So for example a 10min Video (mp4) with 4-5 correction layers should be an easy thing for the new mac..
Yes I got classes in photoshop and I'm learning editing in premiere at the moment. AE was just a little "trying out" the application but im fascinated of the unlimited possibilities in AE so I want to get used to AE too in the future.
What are your components in your old macbook like? because if the radeon 450 2gb is even with your graphic card it should work to use the applications without the more expensive radeon 460 4gb, do you agree?
thanks for helping me out!