A 318, compared with other engines out there in production, either before or after the 318 was produced, was and is still a mid to large displacement engine.
When I look at other engines out there with similar displacement, there are countless examples of really high HP 5.2ish liters of displacement.
I really love all things mopar so hey I love a fast 318. However, all other things being equal, a 273/318/340/360/390/408/422 all occupy the same exact outer footprint, and likely a very similar weight. All other things considered displacement will still rule the day. To each his own though, by virtue we're all mopar guys, none of us are choosing the mainstream or easy path.