I'd be very happy to go on one of those vessels on that great river but as explained in the post on the Murray River the characteristics of each river drives the design, and over the years that creates a tradition of naval architecture.
And there's a fantastic example of a paddle steamer that looks just right for the Thames in the PS Waverley, currently in the capital. According to Wikipedia the PS Waverley is the last seagoing passenger-carrying paddle steamer in the world
As can be seen in the picture below it looks just right as it heads into the Pool of London passing the Tower:
The Thames was busy with Thames Clippers and sight-seeing boats and it was low water, making the river narrow, so it was a neat job to turn her round just by London Bridge with St. Pauls in the background:
Then it was back down river under Tower Bridge which was raised again, making a magnificent sight: