Why give the job to a cricketer. Shouldn't you be looking for a successful business person ?
I think it depends on what you want from the job - for me Tom Harrison's role is that filled by a successful business person, the director of cricket needs to be someone who understands:
1. the style of cricket that is needed to win cricket matches - in each format - which is defined by the captain with help from the coach
2. be able to challenge the captain to ensure that approach will be impactful - so must understand the modern game and be a strategic thinker
3. should work with the captain and coach to help the selectors identify the players who can deliver that game plan
4. where those players don't exist, work with the coaches at the counties to find and create those players
Personally I don't see this as a full time role, but I do think it needs to be a someone with significant cricket experience