First, let's get the coupe discussion out of the way. No one buys non-performance coupes anymore. None of the competition come in a two-door form factor. Honda was the last holdout, and coupes made a small percentage of total sales. Coupe fans may not mind the downsides if it nets them something a little sportier and a little less common, but they're in the minority. As much as we may don't want to believe it, this is a business and focusing on a single bodystyle saves time and money.
The argument against the V6 is much the same as that of the coupe: no one buys them. They're expensive and inefficient. Just a handful of competitors like the Toyota Camry, Volkswagen Passat, and Ford Fusion still offer a V6. For years, Americans demanded more power than other markets. That's how we get oddballs like the mid-mounted supercharged inline-four in the Toyota Previa - we wanted power and a V6 wouldn't fit.
Every mainstream automaker is downsizing engines in the wake of ever stricter standards on fuel economy and emissions. As wonderful as the Honda J engine may be, it's a 20-year-old design that doesn't fit the expectations or requirements for a modern midsize sedan. It's not like the replacement is a dud. Honda is still offering an engine that has far more power than what's needed for a car like the Accord.
The 2.0-liter turbocharged inline-four is heavily based on the new Honda Civic Type R engine, and there are few complaints about it in that car. Yes, it's been reworked and returned for use in the Accord, but the bones are still there. With 252 horsepower, it is down on power compared to the V6, but torque is up 21 lb-ft from 252 to 273 lb-ft. Since it comes on as soon as 1,500 rpm, it will feel stronger pulling away from stop lights.
As with most modern turbocharged engines, a slight tune should yield substantial gains in power. Look at what Hondata can do with the 1.5-liter turbocharged inline-four in the Civic Si (the base engine in the Accord). It's not crazy to think that the Accord could easily make 300 horsepower with minor modifications to the 2.0-liter.
Finally - and I think what most people are forgetting - you can order a manual with both turbocharged engines. This is key and something that no other competitor offers. We all decry the loss of three-pedal cars, but Honda is here offering a manual on the top-spec engine in a midsize sedan. An 2.0-liter Accord Sport with a manual and a slight tune could be a real sleeper.
The outgoing Accord V6 coupe may have been quick, but it wasn't a great handling car. If anything, this new model will be better. The weight distribution is improved to 60/40 front/rear and the new adaptive dampers could improve cornering. Even if that's not the case, this new Accord is sure to be comically quick for a midsize sedan. It may have lost its V6, but the new 10th-gen Accord is still a real hot rod.