I am not sure that either of these fit into the description of the categories in the sticky so I apologise for the non-standard categorization.
1. Add an optional resolution filter to Options > Video to restrict the list of resolutions to a particular ratio [4:3|16:9|16:10]. Alternatively add the ratio to the text in the drop-down list of available ratios. This may make it easier for users to reduce their screen resolution while maintaining the aspect ratio to improve performance.
2. The addition of 'tool tips' for each option would be welcome. Maybe a short explanation of what the option does and what impact it has on performance/the type of resource it consumes? It may make it easier for users to decide what options should be turned off/down to improve performance.