Microsoft’s Greg Sullivan: We are bringing the look and feel of Windows Phone 8 to the Nokia Lumia 900, all other Windows Phones

Speaking to Laptop Magazine, Windows Phone senior product manager Greg Sullivan has confirmed that all Windows Phone 7 handsets will get the new Windows Phone 8 start screen.

When asked “Will all existing Windows Phones get the 7.8 update at the same time?” he said:

Sullivan: We appreciate the desire to put the latest software on the hardware that I own. To the degree that that’s feasible, we’re going to enable that. I’ll compare that approach to the Android approach, which is that the No.-1-selling platform right now, but Google doesn’t seem to care if you get an upgrade to your OS.

When asked “So what are you offering with Windows Phone 7.8?”

Sullivan: On the existing Start screen, the Live Tiles didn’t go all the way to the edge of the screen. There were two sizes, and these sizes weren’t user configurable. Now we’re using the whole screen, we added a small size Live Tile, and every single tile can be resized by the user. To get to your apps, you still just swipe over.

Note that Greg made no mention of any other applications or features.

When asked why some-one would buy a Nokia Lumia 900 right now he said “…what we are going to bring is the look and feel of Windows Phone 8 to phones with Windows Phone 7.8.”

“The sense that we just bought something and we don’t want to be left behind is what we’re delivering on,” says Sullivan to Mashables. “Nokia is doing a bunch of works to keep this fresh. They’re going to continue to invest in the Lumia line and add new capability and new functionality.”

Speaking to Mashables, he admitted that Windows Phone 8 could have been brought to the Lumia, but at great cost and little benefit.

“All of the work we would have had to do to get it on this architecture — and then there’s no benefit,” said Sullivan.

He noted that the massive Windows ecosystem with an installed base of 1.3 billion computers will encourage developers to code for Windows 8, which will boost the Windows Phone 8 app ecosystem.

“It’s going to be very easy for them to also target our platform. This was not true before, before the shared core and native code,” he said.

This huge influx of applications will of course not run on Windows Phone 7.8 handsets.

Read the full interview, which drops a hint of email dictation in Windows Phone 8, at Laptop Magazine here.