The International Space Station is the most expensive object humanity has ever built. You think that the reason we are slow at terraforming Mars is because we're debating about life there?! No. The reason we're slow is because it would take millennia and incomprehensible amounts of money.
I say we land there with humans, spend a few decades checking the place out, then begin with the terraforming.
You misunderstand me. The non-contamination argument is offered reflexively to any proposal for work on Mars - from sending more landers to manned exploration. It's an obstruction to funding and research, rather than to terraforming directly - just as news like this is an encouragement.
I do not think terraforming need be terribly expensive, incidentally. We already map a great number of asteroids and comets out of awareness that if a sufficiently large one were to hit the Earth its impact would be devastating. Our best understanding at present of how to deal with the possibility of such an impact is to give the item a slight nudge that will alter its trajectory during a non-terminal interaction with Earth's gravitational field. We have already matched speeds with and made very close observations of asteroids, and our observational abilities are constantly improving. So to begin the work of terraforming Mars, I would begin looking for asteroids with large quantities of ice (or ammonia or other appropriate compounds) that are likely to intersect closely with Mars' orbit, and give them an encouraging nudge.
It annoys me that since the two rovers we've sent so far have worked so well, our response is to spend years developing a New and Better Rover at great expense, rather than launching launching a large number of rovers that use the existing design which is already known to work, and which can be done without any additional research whatsoever.
I was under the impression that Mars once had an atmosphere, but its lack of a strong magnetic field means that the solar winds sweep that all away. If true, that means that terraforming would have to involve 'jump-starting' Mars' magnetic field, which would probably involve a great deal more difficulty.
Wait that tin can floating around above us is the most expensive thing we've built? Wow, that's sort of kills all the dreams of things like building an enterprise size ship in space for a long while.
I guess it's a function of cheap transport to LEO. If we get that, other things will follow. Go Space X!
I say we land there with humans, spend a few decades checking the place out, then begin with the terraforming.