Hi TeeK,
Generally, design characteristics for maximising wave count are as follows:
Foam is your friend - a board with more volume will paddle easier, float the surfer more reducing drag and catch waves sooner.
Length is good - a longer board glides through the water easier and is therefore easier to paddle, catching waves sooner and prolonging session time as you don’t burn your arms out paddling back out and maintaining position. Also when up and riding, the boards glide generates speed itself and reduces the need for pumping technique allowing the board to glide through sections, and reduces chance of bogging, ultimately extending the ride.
Rocker - a lower rocker helps with paddling as the board isn’t pushing as much water and the path that the water flowing under the board takes isn’t as disrupted causing easier and fast release and a smoother, faster paddle efficiency. It also gets up and planing quicker meaning easier paddling and faster down the line speed.
Width - a wider board is generally more stable and can help maximise your time up and riding.
All of that being said, I have listed these feature’s specifically for their benefit paddling. As you noted, They can have a negative effect on the experience when up and riding and they may not be suited to waves of more consequence with steeper faces and later take offs so as with all things board building it’s finding a balance of all the elements to fit but the surfers body, their ability and the ability to waves they are riding.
The trade offs are (again speaking in sweeping generalities):
Too much volume can make it difficult to sink the rail and the board will sit on top of the water, not engage the wave properly and be difficult to control. They are also harder to duck dive. (The Volume/displacement of a board and its relation to an individual surfer is a very personal thing as the weight of a surfer and the power they can produce will affect a boards performance differently to that of a different surfer.)
Length - bigger boards are (generally) harder to fit into steeper/more hollow waves, are extremely difficult for the average surfer to survive a late take off, are less manoeuvrable and slower turning due to swing weight and are again very hard to duck dive.
Low rocker - can struggle to fit properly into the pocket of steeper hollow waves (length dependant), more susceptible to pearling.
Width - can spin out at higher speeds and on faster steeper waves. Depending on the outline curve; it can introduce drag slowing paddle efficiency. Harder to duck dive.
There are no hard and fast rules as every surfer’s body and ability is unique to them generally but a board that maximises wave count will lead to faster progression to a level where the surfer can start honing their technique, specialising their equipment to suit more advanced conditions and specific sensations there are seeking.
The key to maximising wave count is paddle efficiency and a longer board with more volume will benefit most people until they are at the point where they are learning to put a board on rail and start progressing their turning.
A board in the 7-8’ range with a low to medium rocker and about 3” thickness will be a great improver board for most people coming down from a longer beginners board.
Lots of huge sweeping generalisations there but I hope it helps.