Your description is rather unspecific and I may misunderstand your approach. Therefore I will try to near me from another direction.
Ideally you have a well designed data-model. And then you put a few list-boxes on the left/right/top of a sheet and in the center you have some charts/tables - maybe also with the auto-minimize feature or in containers to provide an easy choice of a few views. Until now just simple expressions with as less as possible of set analysis and/or variables - only a few mandatory needed ones and/or for heavy redundant parts - will do a good job. Different requirements in regard to global/dashboard/analysis/detailed-data views or special select/print/export/meta-data views are distributed to different sheets. The user selects simply what he/she wants to see. No buttons or other triggers for actions/macros to show/hide objects, selecting any values, jumping anywhere or doing other magic things.
Building a well working UI becomes a matter of a few hours. To top the excellent usability which comes with this simple approach is quite hard and will need some efforts.
Of course there will be always some specific requirements which aren't solvable with the basics and for them it's possible and sensible to dive deep into the tool box to find appropriate solutions - on top of a simple approach like above hinted.
Starting with a revers approach to wrap Qlik with a complete own usability goes IMO in the wrong direction. Why making simple things more complex, more complicated and of course more expensive as needed? You will learn a lot but it's not an effective way of work. After some years of work you will have the knowledge and capabilities to do such stuff in a equally or even better way but especially if you are also responsible to administer and maintain n applications within an environment - you won't do it else you will keep the things as simple as possible.
Probably not what do you want to hear ... and yes I think your variable-calculation could have a significantly impact on the performance because each interaction triggers a re-calculation.
- Marcus
