As far as I can tell from the documentation, the Echo Plus will at least have a ZigBee radio and the ability to act as a hub for those devices, according to Simple setup devices compatible with Echo Plus:
Echo Plus has a built-in hub that seamlessly connects and controls ZigBee smart devices such as light bulbs and plugs without the need for separate hubs or apps. With simple setup, connecting Echo Plus to the devices below is easy. Just say "Alexa, discover my devices" and Echo Plus will discover and set up your devices.
Like other Echo devices, Echo Plus can connect to hundreds of Wi-Fi and Bluetooth smart home devices with the Alexa app, such as lights, outlets, TVs, thermostats, cameras, and more. Shop all smart home products.
It sounds like the software will also be upgraded to match expectations of a smart hub, according to the info page:
Group multiple actions together at scheduled times or with a single voice command, like securing your home by locking the doors and turning off the lights when you go to bed.
The scheduling and grouping would seem to reduce the need for a hub if you're just setting up a basic home automation system.
For you, if you're hoping to control lights, it might be worth having an Echo Plus. Some of the lighting devices that support the new 'simple setup' might be interesting to you, particularly if you don't already have any hubs set up. However, many smart lights and switches are already compatible with the original Echo, so check with the products you're interested in to see if they'd benefit from an Echo Plus.