When you render a mix you really should be able to tick a box and force it to downmix it to true mono, a mono file. People doing voiceovers and similar have to jump through a few routing hoops to make that happen and in such a nice product it really should be unnecessary.
If you look at Cubase / Nuendo (manual text below) and some others "Export Mixdown", you'll often see an option / check for "Mono Downmix".
In the Audio Engine Output section, specify whether you want to export all subchannels of a multi-channel bus as separate mono files (Split Channels), downmix all subchannels to one mono file (Mono Downmix), or export only the left and right channels of a multi-channel bus to a stereo file (L/R Channels).
Thanks.
