Playing devil's advocate...
Can anyone provide a single reason the new engines will ruin the sport?
I can give you my reasons for not liking the new engine
1) they are anti green
2) wasting money to make a new engine when the current engine works fine and could be further developed
3) why build a new engine that is less powerful than the current engine
4) it's not leading edge, it's basically an engine that could be made in someone's back yard from parts you can readily purchase - a 12K reving 600HP engine is a pathetic donk by today's standards and will be more pathetic in 2 years time
That should do for now ......
1) That's debatable. The specification is based around the FIA's change to basing engine formulas on fuel efficiency, which takes effect around the same time.
You can debate it all you like, but the engine is not going green. Look at the money needed to develop the new engine. Look at how much resources will be used, and, in the end they will manufacture a few engines. The new engine is also spec'd on using rare earths which are a far rarer resource than oil. What's more it's mined by slaves earning a few dollars and the world supply comes from China. And, in the end, all these resources will be wasted on producing an engine that does no more in terms of performance, we just have to waste a huge amount of the worlds resources to make them.
2) That's a spurious complaint at best. The teams keep pointing to not developing the current engines any further as a cost-cutting measure. They do it anyway. But that's beside the point.
Nice word, no truth in it, but nice word. The fact is a huge amount of extra money will be spent to make an engine that does less. The same engine could be enhanced at a fraction of the cost, and we'd get more power rather than less.
3) Fuel efficiency. But since the aim is to come as close to the current speed as possible, raw power isn't relevant. If the speed is similar, the power doesn't matter.
So fuel efficiency is a goal of F1!
Waste hundreds of millions of dollars to make a few engines that will use a little less fuel. Ridiculous proposition. At least you admit the engines will be less powerful. And, to put the power of the new engine into perspective, it will be about what GP2 produces now. Brilliant, not long we will be able to have one of those races where they line up a sedan, a GT and an F1, only thing is, it will be the GT taking off last.
4) That's just a load of BS. I dare dare, I DOUBLE DARE YOU to build a turbo-charged I4 with accompanying Energy Recovery Systems to F1 standards delivering the same power, weight and cost as, say, Cosworth do in your back garden and sell it to an F1 team. Go ahead. Do it. Don't be surprised when they laugh in your face because you've failed miserably to build anything even remotely in the same league as what Mercedes, Renault & co. turn out.
{ignoring BS insult} Go to youtube and search for 4 cyl turbo 600HP. When you get tired of cycling through the golfs and hondas come back and tell me it's not possible. Honestly, get yourself into a garage sometime soon, a 12K reving turbo engine - lol - that's a challenge?
I said elsewhere that I think the FiA, as usual, have got the new engine spec all wrong. They try to make mountains of rules to regulate. What they achieve is to stifle creativity. Instead of writing complex rules they should simply set an objective. In 2013 all teams will be give an annual fuel allowance and a per event fuel allowance, you can even say it will be reduced by 5% per year. Now, if a team wants to make a V12 let them, if another team wants to go turbo, fine.
these amazing new techno ones? I would prefer France over it any day! 
and the xhaust should have to be forced to be shaped a certain way to make the engine revs bellow. >_> I'll take fake noise over nothing if I have to choose. 
