Depends whether this is meant to be an absolute reboot, a quasi-reboot like the current movies are to TOS or a prequel/ sequel to TNG and the movies.
If they want someone who resembles Stewart, Hardy has to be the obvious choice, even though I never found him that convincing as a Picard clone in Nemesis. James Marsters might be an interesting choice. Kevin McKidd might also fit the bill.
If they're after someone who is not really physically like Stewart but brings similar authority and presence, then the likes of James Purefoy, Ciaran Hinds or Jean Reno would also work.