One of my favourite reads was Brian Stanley's 'Christ and the flag'. This book looked at the rise of Empire as a function of Christian missionary zeal. The missionaries made the tracks into Africa and the traders, explorers, colonialists and others followed. Conquest and exploitation of natural resources (including of course people) came about as a result of the Church's actions but not its intentions. The problem was (is?) that people saw the results of Empire and blamed the Church for providing the means by which they were brought into being.
Taking this as an example, seems to me that the key to pioneering is that we need people to be where, in this case, Church is perceived not to be awaiting the arrival of those who come to conqueror (for Christ). Just as Empire used the paths trodden and the places inhabited by missionaries, so to do Pioneers. This means that when we send Pioneers into a place, there needs to be people who have established or settled that place beforehand so that there is a core membership of any groups that come into being. There aren't there to run things as leaders but are there to add normal Christians who by being salt and light bring the kingdom of God (basiliea) into that place.
One of the big problems with some aspects I have seen with pioneering is that there is a tendency towards being so much unlike 'Church' that the groups that come into being are also un like Christians. Rather than draw lines and preach 'hardline' Christianity, there is at times something that feels rather syncretic and unable to correct lest those newbies feel judged or corrected. The Empire-builders had no problems with this and their evangelistic zeal (including teaching the national anthem) did them much credit, even if it was misplaced and ill thought through!
So here's a bit more thinking on the pioneering front, hope it is proving useful, challenging, funny (perhaps in an "Oh my, look what he's written now!" sort of way!).
Pax