We can take this to mean either "many" Windows Phone 7 devices, or "many" touchscreen-only WP7 devices. Either way, we're thrilled. And that's not to say we weren't expecting more. Microsoft's push to CDMA carriers will greatly increase their already respectable sales.
The HTC 7 Pro will be the first Windows Phone 7 device on Sprint, and should do fairly well. HTC may be excited to have a temporarily exclusive grip on the #3 carrier, as their devices on AT&T have been overshadowed by the Samsung Focus.
Many users will likely echo the concerns featured in the tweet below, as they would rather have a sleeker, more iPhone-like form factor, and sacrifice the full keyboard.
source: @SPRINT via WMPoweruser