I just ordered lots of 20x20 and 25x50 mm lasercut MDF bases for old and new figures plus some 40x80 and 50x100mm ones.
The infantry I will put single based on my existing movement trays (all magnetized), so there will be no difference to WAB/WAC.
Three bases wide and two deep is normal 6x4 figures which was default before too, plenty of trays existing.
There is an advantage having 4 models infantry on only one base but disadvantage to integrate a commander or use some of that figures as skirmisher sometimes.
The commander and general figures can easily put into front rank single square-base, avoiding round-based ones behind units.
Those single models rarely move on their own on foot or horse, so no need for round-based ones for me.
Only the skirmishers need a new way to be based, but I simply use those base empty as small diorama and put two single based models on it if I need them. This way I can use various models as skirmisher or part of formed unit and transporting 20 skirmishing bases is easier.
So the effort to move to Swordpoint is really not an issue even if you still prefer single based figures.
And an idea to display a unit is discouraged: Put the standard bearer in the last rank instead of front to signal that status. There is no command team any longer for Swordpoint I know but units look nicer with a standard in the front and you can avoid using marker beside the unit.