Hi Stephan,
Thank you for providing this feedback and for the specific affected areas. This is very timely (as @Sarah Nau‚ mentioned above). We are investing heavily and prioritizing both usability and performance enhancements to improve things going forward.
These global and specific improvements won't all happen overnight, but feedback like this helps us know where to focus and prioritize our efforts. I can say that optimizing the task list/detail pages area is already on our backlog.
For now, can you please log a ticket here: https://one.workfront.com/s/support? This way we can have our support team do some testing on our side and make some suggestions. We will use this data to prioritize improvements that will have the biggest positive impact for you, your users, and the community.