I think you're right about both the writing and about Hartnell (although he does seem not to be there for a lot of the episodes!). He is hilarious in 'The Gunfighters'.

Watching 'The War Machines' was fascinating: my first impression was, "Wow, this is a complete revamp of this show, really fresh and exciting!" and then you think, "And this is exactly what it's going to be like until the Holmes-Hinchcliffe era!"