Could you specify what you see as a real problem in simpreps workflow ?
There are at least 3 - 4 ways to define simplified representation, easiest has no UI at all and is the fastest one (select component / RMB / Representation). There is "intermediate" way defining simprep by components list in View Manager / simprep / Properties. - this should also be a fast one. And for users who need fully functional simprep definition - with preview (new capability), rules, proximity and size analysis - you go to the bigger dialogue which - due to preview - may be a little laggy (collapsing Preview area eliminates this lags).
Hope this helps,
- Vlad