The thing to remember is that as you increase in bullet diameter, you will generally have to increase bullet weight to keep with a standard of ballistic performance.
Yes, the larger bullet diameters will have more visual effect when they land on target, but again, only if they are placed in the correct place. A gut shot deer is a gut shot deer weither your shooting a 243 or a 408 CT, makes no difference, you will more then likely loose the animal unless you have good tracking conditions.
The 7mm rounds are a good balance of energy, penetration, ballistic performance and ease of shooting. Rounds such as the 7mm WSM
are great for long range shooting on deer size game and even elk with proper shot placement.
At the expense of sounding boring, there is nothing wrong with the old 7mm Rem Mag either. More performance then the 7mm WSM and nearly as popular as the 270 and 30-06. Just not SEXY!!
If you want bang flops, use a quality bullet in an accurate rifle and put the bullet where it needs to go for a one shot kill. The rest is mearly details but that is also the fun part!!
Hell, if everyone only had one rifle, I would be stocking shelves at Walmart instead of building rifles!!!