Thanks everyone for your superb posts so far
As expected, everyone falls one side or the other!
Both hold merits and drawbacks. One point worth mentioning is using proprietry software like Max/Maya etc should be ruled out. Access to this software can not be taken for granted. I think the only way would be for a bespoke solution.
After everyone thoughts up til now, I'm tending towards a hybrid solution of free form and block based
Also, If someone could make post a list of editors to investigate that would be cool.