Actually 4e was incredibly easy to do TotM if you were used to it. WE came to 4e straight from 1e and had no issue doing TotM in 4e. I actually think it was easier than 1e becuase everything was defined so well. I constantly used grid paper to keep track of things in 1e, but found I didn't need that in 4e.I don't think the various groups I've played with have really required a grid for any edition except 4th. All others have easily been done with theatre of the mind.