I will be convinced about Maul = Grievous when I see a flawlessly smooth scene which tells the story of it. I'm not holding my breath.
Agreed with those who want less subtitles than BotF - what about MagFan's dialogue for Jar Jar, but spoken in English? Even the Neimoidians could be re-dubbed in English with new dialogue.
I repeat that making Sidious into Dooku will probably have a negative effect on MTH's streamlining plans. Beware of change for change's sake.