There's nothing at all wrong with lever shocks; your friends are no doubt only familiar with the much softer ones fitted to cars with IRS. But the stock TR4 shocks will easily provide all the damping you need, if they are in good condition.
One way to test is to try to 'bounce' the car, by putting your weight rapidly on and off over each corner in turn. The suspension should not oscillate at all, only rise once and then immediately stop at it's normal height. If it rises a second time, there is a problem with the shocks (or links, etc.).
Usually a visual inspection will reveal bad bushings and so on; although you may need to disconnect the links temporarily to find if their joints are tight. The cylindrical end of each link is supposed to be bonded (not just a bushing) so the rubber has to deform as the suspension moves. Not unusual to find the bond broken.
Also check that the two bolts holding each shock to the frame are tight. They have a tendency to work loose, which can cause poor ride.
Most common cause of rough (as opposed to too bouncy) ride, IMO, is the leaf springs. Over time, they get rusty between the leaves and no longer work smoothly, which literally makes them act like a solid bar for small bumps (an effect known as stiction). Either new springs, or disassembling, cleaning and lubricating the old ones, will make a world of difference.
There are several types of tube shock conversion around; but they all suffer from a serious flaw. Because they must be located farther away from the frame mounting point, they put more force into the bracket, which will cause it to flex and eventually break. I don't recommend them.