There are cases when texts may have minor variations in colour, resulting from the OCR that produced the original PDF. So, an improvement has to allow the merge of such runs.
Technical notes. Conditional parameters should have an option which would specify a value to measure the colour distance allowed for merging the consequential runs. Also, it may be worth turning this functionality with an additional switch/flag/parameter.
For additional details and experiments please refer to the attached document and its UI: